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SQL++ for Mobile

    Description - How to use SQL++ Query Strings to build effective queries with Couchbase Lite for React Native
    Related Content - Live Queries | Indexes

    N1QL is Couchbase’s implementation of the developing SQL++ standard. As such the terms N1QL and SQL++ are used interchangeably in all Couchbase documentation unless explicitly stated otherwise.

    Introduction

    Developers using Couchbase Lite for React Native can provide SQL++ query strings using the SQL++ Query API. This API uses query statements of the form shown in Example 1. The structure and semantics of the query format are based on that of Couchbase Server’s SQL++ query language - see SQL++ Reference Guide and SQL++ Data Model.

    Running

    Use Database.createQuery to define a query through an SQL++ string. Then run the query using the Query.execute() method.

    Example 1. Running a SQL++ Query

    const query = database.createQuery('SELECT META().id AS thisId FROM inventory.hotel WHERE city="Medway"');
const resultSet = await query.execute();

    Query Format

    The API uses query statements of the form shown in Example 2.

    Example 2. Query Format

    SELECT ____
FROM ____
JOIN ____
WHERE ____
GROUP BY ____
ORDER BY ____
LIMIT ____
OFFSET ____

    Query Components

    1. The SELECT clause specifies the data to be returned in the result set.

    2. The FROM clause specifies the collection to query the documents from.

    3. The JOIN clause specifies the criteria for joining multiple documents.

    4. The WHERE clause specifies the query criteria. The SELECTed properties of documents matching this criteria will be returned in the result set.

    5. The GROUP BY clause specifies the criteria used to group returned items in the result set.

    6. The ORDER BY clause specifies the criteria used to order the items in the result set.

    7. The LIMIT clause specifies the maximum number of results to be returned.

    8. The OFFSET clause specifies the number of results to be skipped before starting to return results.

    We recommend working through the SQL++ Tutorials as a good way to build your SQL++ skills.

    SELECT Clause

    Purpose

    Projects the result returned by the query, identifying the columns it will contain.

    Syntax

    Example 3. SQL++ Select Syntax

    select        = SELECT _ ( ( DISTINCT | ALL ) _ )? selectResults
selectResults = selectResult ( _? ',' _? selectResult )*
selectResult  = expression ( ( _ AS )? _ columnAlias )?
columnAlias   = IDENTIFIER

    Arguments

    1. The select clause begins with the SELECT keyword.

      • The optional ALL argument is used to specify that the query should return ALL results (the default).

      • The optional DISTINCT argument is used to specify that the query should return distinct results.

    2. selectResults is a list of columns projected in the query result. Each column is an expression which could be a property expression or any expression or function. You can use the * expression, to select all columns.

    3. Use the optional AS argument to provides an alias for a column. Each column can be aliased by putting the alias name after the column name.

    SELECT Wildcard

    When using the * expression, the column name is one of:

    * The alias name, if one was specified.
* The data source name(or its alias if provided) as specified in the [FROM clause](https://cbl-dart.dev/queries/sqlplusplus-mobile/#from-clause).

    This behavior is inline with that of SQL++ for Server - see example in Table 1.

    Table 1. Example Column Names for SELECT *

    Query Column Name

    SELECT * AS data FROM _

    data

    SELECT * FROM _

    _

    SELECT * FROM _default

    _default

    SELECT * FROM users

    users

    SELECT * FROM users AS user

    user

    Example

    Example 4. SELECT Examples

    SELECT * ...;
SELECT user.* AS data ...;
SELECT name fullName ...;
SELECT user.name ...;
SELECT DISTINCT address.city ...;

    1. Use the * expression to select all columns.

    2. Select all properties from the user data source. Give the object an alias of data.

    3. Select a pair of properties.

    4. Select a specific property from the user data source.

    5. Select the property city from the address data source.

    FROM Clause

    Purpose

    Specifies the data source and optionally applies an alias (AS). It is mandatory.

    Syntax

    Example 5. FROM Syntax

    from             = FROM _ dataSource
dataSource       = collectionName ( ( _ AS )? _ collectionAlias )?
collectionName   = IDENTIFIER
collectionAlias  = IDENTIFIER

    Here dataSource is the collection name against which the query is to run. Use AS to give the collection an alias you can use within the query. To use the default collection, without specifying a name, use _ as the data source.

    Example

    Example 6. FROM Examples

    SELECT name FROM testScope.user;
SELECT user.name FROM testScope.users AS user;
SELECT user.name FROM testScope.users user;
-- These queries use the default scope and default collection (_default._default) in Couchbase.
SELECT name FROM _default._default;
SELECT user.name FROM _default._default AS user;
SELECT user.name FROM _default._default user;

    JOIN Clause

    Purpose

    The JOIN clause enables you to select data from multiple data sources linked by criteria specified in the ON constraint. Currently only self-joins are supported. For example to combine airline details with route details, linked by the airline id - see Example 7.

    Syntax

    Example 7. JOIN Syntax

    join            = joinOperator _ dataSource ( _ constraint )?
joinOperator    = ( ( LEFT ( _ OUTER )? | INNER | CROSS ) _ )? JOIN
dataSource      = collectionName ( ( _ AS )? _ collectionAlias )?
constraint      = ON _ expression
collectionName  = IDENTIFIER
collectionAlias = IDENTIFIER

    Arguments

    1. The JOIN clause starts with a JOIN operator followed by the data source.

    2. Five JOIN operators are supported:

      • JOIN, LEFT JOIN, LEFT OUTER JOIN, INNER JOIN, and CROSS JOIN.

      • NOTE: JOIN and INNER JOIN are the same, and LEFT JOIN and LEFT OUTER JOIN are the same.

    3. The JOIN constraint starts with the ON keyword followed by the expression that defines the joining constraints.

    Example

    Example 8. JOIN Examples

    SELECT users.prop1, other.prop2
FROM testScope.users
JOIN users AS other ON users.key = other.key;

SELECT users.prop1, other.prop2
FROM testScope.users
LEFT JOIN users AS other ON users.key = other.key;

    Example 9. Using JOIN to Combine Document Details

    This example joins the documents from the routes collections with documents from the airlines collection using the document ID (id) of the airline document and the airlineId property of the route document.

    SELECT *
FROM inventory.routes r
JOIN airlines a ON r.airlineId = META(a).id
WHERE a.country = "France";

    WHERE Clause

    Purpose

    Specifies the selection criteria used to filter results. As with SQL, use the WHERE clause to choose which results are returned by your query.

    Syntax

    Example 10. WHERE Syntax

    where = WHERE _ expression

    Arguments

    1. WHERE evalates the expression to a BOOLEAN value. You can combine any number of expressions through logical operators, in order to implement sophisticated filtering capabilities.

    Example

    Example 11. WHERE Examples

    SELECT name
FROM testScope.employees
WHERE department = "engineer" AND group = "mobile"

    GROUP BY Clause

    Purpose

    Use GROUP BY to group results for aggreation, based on one or more expressions.

    Syntax

    Example 12. GROUP BY Syntax

    groupBy  = grouping ( _ having )?
grouping = GROUP BY _ expression ( _? ',' _? expression )*
having   = HAVING _ expression

    Arguments

    1. The GROUP BY clause starts with the GROUP BY keyword followed by one or more expressions.

    2. The GROUP BY clause is normally used together with aggregate functions (e.g. COUNT, MAX, MIN, SUM, AVG).

    3. The HAVING clause allows you to filter the results based on aggregate functions - for example, HAVING COUNT(airlineId) > 100.

    Example

    Example 13. GROUP BY Examples

    SELECT COUNT(airlineId), destination
FROM inventory.routes
GROUP BY destination;

SELECT COUNT(airlineId), destination
FROM inventory.routes
GROUP BY destination
HAVING COUNT(airlineId) > 100;

SELECT COUNT(airlineId), destination
FROM inventory.routes
WHERE destinationState = "CA"
GROUP BY destination
HAVING COUNT(airlineId) > 100;

    ORDER BY Clause

    Purpose

    Sort query results based on a expression.

    Syntax

    Example 14. ORDER BY Syntax

    orderBy  = ORDER BY _ ordering ( _? ',' _? ordering )*
ordering = expression ( _ order )?
order    = ( ASC | DESC )

    Arguments

    1. The ORDER BY clause starts with the ORDER BY keyword followed by one or more ordering expressions.

    2. An ordering expression specifies an expressions to use for ordering the results.

    3. For each ordering expression, the sorting direction can be specified using the optional ASC (ascending) or DESC (descending) directives. Default is ASC.

    Example

    Example 15. ORDER BY Examples

    SELECT name
FROM testScope.users
ORDER BY name;

SELECT name
FROM testScope.users
ORDER BY name DESC;

SELECT name, score
FROM testScope.users
ORDER BY name ASC, score DESC;

    LIMIT Clause

    Purpose

    Specifies the maximum number of results to be returned by the query.

    Syntax

    Example 16. LINIT Syntax

    limit = LIMIT _ expression

    Arguments

    1. The LIMIT clause starts with the LIMIT keyword followed by an expression that will be evaluated as a number.

    Example

    Example 17. LIMIT Examples

    SELECT name
FROM testScope.users
LIMIT 10;

    OFFSET Clause

    Purpose

    Specifies the number of results to be skipped by the query.

    Syntax

    Example 18. OFFSET syntax

    offset = OFFSET _ expression

    Arguments

    1. The offset clause starts with the OFFSET keyword followed by an expression that will be evaluated as a number that represents the number of results to be skipped before the query begins returning results.

    Example

    Example 19. OFFSET Examples

    SELECT name
FROM testScope.users
OFFSET 10;

SELECT name
FROM testScope.users
LIMIT 10
OFFSET 10;

    Expressions

    An expression is a specification for a value that is resolved when executing a query. This section, together with Operators and Functions, which are covered in their own sections, covers all the available types of expressions.

    Literals

    Boolean

    Purpose

    Represents a true or false value.

    Syntax

    Example 20. Boolean Syntax

    boolean = ( TRUE | FALSE )
    Example

    Example 21. Boolean Examples

    SELECT value
FROM testScope.testCollection
WHERE value = true;

SELECT value
FROM testScope.testCollection
WHERE value = false;

    Numeric

    Purpose

    Represents a numeric value. Numbers may be signed or unsigned digits. They have optional fractional and exponent components.

    Syntax

    Example 22. Numeric Syntax

    numeric = -? ( ( . digit+ ) | ( digit+ ( . digit* )? ) ) ( ( E | e ) ( - | + )? digit+ )?
digit   = /[0-9]/
    Example

    Example 23. Numeric Examples

    SELECT
  10,
  0,
  -10,
  10.25,
  10.25e2,
  10.25E2,
  10.25E+2,
  10.25E-2
FROM testScope.testCollection;

    String

    Purpose

    The string literal represents a string or sequence of characters.

    Syntax

    Example 24. String Syntax

    string         = ( " character* " | ' character* ' )
character      = ( escapeSequence | any codepoint except ", ' or control characters )
escapeSequence = \ ( " | ' | \ | / | b | f | n | r | t | u hex hex hex hex )
hex            = hexDigit hexDigit
hexDigit       = /[0-9a-fA-F]/

    The string literal can be double-quoted as well as single-quoted.
    Example

    Example 25. String Examples

    SELECT firstName, lastName
FROM crm.customer
WHERE contact.middleName = "middle" AND contact.lastName = 'last';

    NULL

    Purpose

    Represents the absence of a value.

    Syntax

    Example 26. NULL Syntax

    null = NULL
    Example

    Example 27. NULL Examples

    SELECT firstName, lastName
FROM crm.customer
WHERE contact.middleName IS NULL;

    MISSING

    Purpose

    Represents a missing name-value pair in a dictionary.

    Syntax

    Example 28. MISSING Syntax

    missing = MISSING
    Example

    Example 29. MISSING Examples

    SELECT firstName, lastName
FROM crm.customer
WHERE contact.middleName IS MISSING;

    Array

    Purpose

    Represents an array.

    Syntax

    Example 30. ARRAY Syntax

    array = [ ( _? expression ( _? ',' _? expression )* _? )? ]
    Example

    Example 31. ARRAY examples

    SELECT ["a", "b", "c"]
FROM testScope.testCollection

SELECT [property1, property2, property3]
FROM testScope.testCollection

    Dictionary

    Purpose

    Represents a dictionary.

    Syntax

    Example 32. Dictionary Syntax

    dictionary = { ( _? string _? : _? expression ( _? , _? string _? : _? expression )* _? )? }
    Example

    Example 33. Dictionary Examples

    SELECT { 'name': 'James', 'department': 10 }
FROM testScope.testCollection;

SELECT { 'name': 'James', 'department': dept }
FROM testScope.testCollection;

SELECT { 'name': 'James', 'phones': ['650-100-1000', '650-100-2000'] }
FROM testScope.testCollection;

    Identifier

    Purpose

    An identifier references an entity by its symbolic name. Use an identifier for example to identify:

    • Column alias names

    • Database names

    • Database alias names

    • Property names

    • Parameter names

    • Function names

    • FTS index names

    Syntax

    Example 34. Identifier Syntax

    identifier       = ( plainIdentifier | quotedIdentifier )
plainIdentifier  = /[a-zA-Z_][a-zA-Z0-9_$]*/
quotedIdentifier = /`[^`]+`/

    To use other than basic characters in the identifier, surround the identifier with the backticks ` character. For example, to use a hyphen (-) in an identifier, use backticks to surround the identifier.

    Please note that backticks are commonly used for string literals/interpolation in TypeScript/JavaScript. Therefore, you should be aware that backticks need to be escaped properly to function correctly in TypeScript/JavaScript. For more information, refer to Template Literal Types in TypeScript.

    Example

    Example 35. Identifier Examples

    -- This query uses the default scope and default collection (_default._default) in Couchbase.
SELECT *
FROM _default._default;

SELECT *
FROM test-scope.test-collection;

SELECT key
FROM testScope.testCollection;

SELECT key$1
FROM test_Scope.test_Collection;

SELECT `key-1`
FROM testScope.testCollection;

    Property Expression

    Purpose

    The property expression is used to reference a property of a dictionary.

    Syntax

    Example 36. Property Expression Syntax

    property     = ( * | dataSourceName . _? * | propertyPath )
propertyPath = propertyName ( ( . _? propertyName ) | ( [ _? numeric _? ] _? ) )*
propertyName = IDENTIFIER

    1. Prefix the property expression with the data source name or alias to indicate its origin.

    2. Use dot syntax to refer to nested properties in the propertyPath.

    3. Use bracket ([index]) syntax to refer to an item in an array.

    4. Use the asterisk (*) character to represents all properties. This can only be used in the result list of the SELECT clause.

    Example

    Example 37. Property Expressions Examples

    SELECT *
FROM crm.customer
WHERE contact.firstName = 'daniel';

SELECT crm.customer.*
FROM crm.customer
WHERE contact.firstName = 'daniel';

SELECT crm.customer.contact.address.city
FROM crm.customer
WHERE contact.firstName = 'daniel';

SELECT contact.address.city, contact.phones[0]
FROM crm.customer
WHERE contact.firstName = 'daniel';

    Any and Every Expression

    Purpose

    Evaluates expressions over items in an array.

    Syntax

    Example 38. Any and Every Expression Syntax

    arrayExpression = anyEvery _ variableName _ IN _ expression _ SATISFIES _ expression _ END
anyEvery        = ( anyOrSome AND EVERY | anyOrSome | EVERY )
anyOrSome       = ( ANY | SOME )
variableName    = IDENTIFIER

    1. The array expression starts with anyEvery, where each possible combination has a different function as described below, and is terminated by END.

      • ANY or SOME: Returns TRUE if at least one item in the array satisfies the expression, otherwise returns FALSE.

        + ANY and SOME are interchangeable.

        +

      • EVERY: Returns TRUE if all items in the array satisfies the expression, otherwise returns FALSE. If the array is empty, returns TRUE.

      • ( ANY | SOME ) AND EVERY: Same as EVERY but returns FALSE if the array is empty.

    2. The variableName represents each item in the array.

    3. The IN keyword is used to specify the array to be evaluated.

    4. The SATISFIES keyword is used to specify the expression to evaluate for each item in the array.

    5. END terminates the array expression.

    Example

    Example 39. Any and Every Expression Examples

    SELECT firstName, lastName
FROM crm.customer
WHERE
  ANY contact IN contacts
    SATISFIES contact.city = 'San Mateo'
  END;

    Parameter Expression

    Purpose

    A parameter expression references a value from the api|Parameters assigned to the query before execution.

    If a parameter is specified in the query string, but no value has been provided, an error will be thrown when executing the query.

    Syntax

    Example 40. Parameter Expression Syntax

    parameter = $ IDENTIFIER

    Example

    Example 41. Parameter Expression Examples

    SELECT *
FROM crm.customer
WHERE contact.firstName = $firstName;

    Example 42. Using a Parameter

    const query = database.createQuery('SELECT * FROM crm.customer WHERE contact.firstName = $firstName');
const params = new Parameters();
params.setValue('firstName', 'daniel');
query.parameters = params;
const resultSet = await query.execute();

    Parenthesis Expression

    Purpose

    Use parentheses to group expressions together to make them more readable or to establish operator precedence.

    Example

    Example 43. Parenthesis Expression Examples

    SELECT (value1 + value2) * value 3
FROM testScope.testCollection

SELECT *
FROM testScope.testCollection
WHERE ((value1 + value2) * value3) + value4 = 10;

SELECT *
FROM testScope.testCollection
WHERE (value1 = value2)
   OR (value3 = value4);

    Operators

    Binary Operators

    Maths

    Table 2. Maths Operators

    Op Description Example

    +

    Add

    WHERE v1 + v2 = 10

    -

    Subtract

    WHERE v1 - v2 = 10

    *

    Multiply

    WHERE v1 \* v2 = 10

    /

    Divide - see 1

    WHERE v1 / v2 = 10

    %

    Modulus

    WHERE v1 % v2 = 0

    1. If both operands are integers, integer division is used, but if one is a floating number, then float division is used. This differs from SQL++ for Server, which performs float division regardless. Use DIV(x, y) to force float division in SQL++ for Mobile.

    Comparison Operators

    Purpose

    The comparison operators can for example be used in the WHERE clause to specify the condition on which to match documents.

    Table 3. Comparison Operators

    | Op | Description | Example | | ------------ | ---------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | = or == | Equals | WHERE v1 = v2<br/> WHERE v1 == v2 | | != or &#60&#62 | Not Equal to | WHERE v1 != v2<br/> WHERE v1 &#60&#62 v2 | | > | Greater than | WHERE v1 > v2 | | >= | Greater than or equal to | WHERE v1 >= v2 | | < | Less than | WHERE v1 < v2 | | <= | Less than or equal to | WHERE v1 <= v2 | | IN | Returns TRUE if the value is in the list or array of values specified by the right hand side expression; Otherwise returns FALSE. | WHERE 'James' IN contactsList | | LIKE | String wildcard pattern matching, comparison - see 2. Two wildchards are supported:
    • % Matches zero or more characters.
    • Matches a single character. | WHERE name LIKE 'a%' <br/> WHERE name LIKE '%a' <br/> WHERE name LIKE '%or%' <br/> WHERE name LIKE 'a%o%' <br/> WHERE name LIKE '%_r%' <br/> WHERE name LIKE '%a%' <br/> WHERE name LIKE '%a__%' <br/> WHERE name LIKE 'aldo' <br/> | | MATCH | String matching using FTS | WHERE v1-index MATCH "value" | | BETWEEN | Logically equivalent to v1 >= start AND v1 <= end | WHERE v1 BETWEEN 10 AND 100 | | IS NULL - see 3 | Equal to null | WHERE v1 IS NULL | | IS NOT NULL | Not equal to null | WHERE v1 IS NOT NULL | | IS MISSING | Equal to MISSING | WHERE v1 IS MISSING | | IS NOT MISSING | Not equal to MISSING | WHERE v1 IS NOT MISSING | | IS VALUED | Logically equivalent to IS NOT NULL AND MISSING | WHERE v1 IS VALUED | | IS NOT VALUED | Logically equivalent to IS NULL OR MISSING | WHERE v1 IS NOT VALUED` |

    1. Matching is case-insensitive for ASCII characters, case-sensitive for non-ASCII.

    2. Use of IS and IS NOT is limited to comparing NULL and MISSING values (this encompasses VALUED). This is different from api|QueryBuilder, in which they operate as equivalents of == and !=.

    Table 4. Comparing NULL and MISSING values using IS

    Op Non-NULL Value NULL MISSING

    IS NULL

    FALSE

    TRUE

    MISSING

    IS NOT NULL

    TRUE

    FALSE

    MISSING

    IS MISSING

    FALSE

    FALSE

    TRUE

    IS NOT MISSING

    TRUE

    TRUE

    FALSE

    IS VALUED

    TRUE

    FALSE

    FALSE

    IS NOT VALUED

    FALSE

    TRUE

    TRUE

    Logical Operators

    Purpose

    Logical operators combine expressions using the following boolean logic rules:

    • TRUE is TRUE, and FALSE is FALSE.

    • Numbers 0 or 0.0 are FALSE.

    • Arrays and dictionaries are FALSE.

    • Strings and Blobs are TRUE if the values are casted as a non-zero or FALSE if the values are casted as 0 or 0.0.

    • NULL is FALSE.

    • MISSING is MISSING.

    This is different from SQL++ for Server, where:

    • MISSING, NULL and FALSE are FALSE.

    • Numbers 0 is FALSE.

    • Empty strings, arrays, and objects are FALSE.

    • All other values are TRUE.

    Use the TOBOOLEAN(expr) function to convert a value based on SQL++ for Server boolean value rules.

    Table 5. Logical Operators

    Op Description Example

    AND

    Returns TRUE if the operand expressions evaluate to TRUE; otherwise FALSE.

    If an operand is MISSING and the other is TRUE returns MISSING, if the other operand is FALSE it returns FALSE.

    If an operand is NULL and the other is TRUE returns NULL, if the other operand is FALSE it returns FALSE.

    WHERE city = 'San Francisco' AND status = TRUE

    OR

    Returns TRUE if one of the operand expressions is evaluated to TRUE; otherwise returns FALSE

    If an operand is MISSING, the operation will result in MISSING if the other operand is FALSE or TRUE if the other operand is TRUE.

    If an operand is NULL, the operation will result in NULL if the other operand is FALSE or TRUE if the other operand is TRUE.

    WHERE city = 'San Francisco' OR city = 'Santa Clara'

    Table 6. Logical Operators Table

    a b a AND b a OR b

    TRUE

    TRUE

    TRUE

    TRUE

    FALSE

    FALSE

    TRUE

    NULL

    FALSE, see 5

    TRUE

    MISSING

    MISSING

    TRUE

    FALSE

    TRUE

    FALSE

    TRUE

    FALSE

    FALSE

    FALSE

    NULL

    FALSE

    FALSE, see 5

    MISSING

    FALSE

    MISSING

    NULL

    TRUE

    FALSE, see 5

    TRUE

    FALSE

    FALSE

    FALSE, see 5

    NULL

    FALSE, see 5

    FALSE, see 5

    MISSING

    FALSE, see 6

    MISSING, see 7

    MISSING

    TRUE

    MISSING

    TRUE

    FALSE

    FALSE

    MISSING

    NULL

    FALSE, see 6

    FALSE, see 7

    MISSING

    MISSING

    MISSING

    This differs from SQL++ for Server in the following instances:

      1. Server will return: NULL instead of FALSE.

      1. Server will return: MISSING instead of FALSE.

      1. Server will return: NULL instead of MISSING.

    String Operators

    Purpose

    A single string operator is provided. It enables string concatenation.

    Table 7. String Operators

    Op Description Example

    &#124&#124

    Concatenating

    SELECT firstName &#124&#124 lastName AS fullName FROM testScope.testCollection

    Unary Operators

    Purpose

    Three unary operators are provided. They operate by modifying an expression, making it numerically positive or negative, or by logically negating its value (TRUE becomes FALSE).

    Syntax

    Example 44. Unary Operators Syntax

    unaryOperator = ( + | - | NOT ) _ expression

    Table 8. Unary Operators

    Op Description Example

    +

    Positive value

    WHERE v1 = +10

    -

    Negative value

    WHERE v1 = -10

    NOT

    Logical Negate operator, see 8

    WHERE "James" NOT IN contactsList

    1. The NOT operator is often used in conjunction with operators such as IN, LIKE, MATCH, and BETWEEN operators.

      • NOT operation on NULL value returns NULL.

      • NOT operation on MISSING value returns MISSING.

    Table 9. NOT Operators

    a NOT a

    TRUE

    FALSE

    FALSE

    TRUE

    NULL

    FALSE

    MISSING

    MISSING

    COLLATE Operator

    Purpose

    Collate operators specify how a string comparison is conducted.

    Usage

    The collate operator is used in conjunction with string comparison expressions and ORDER BY clauses. It allows for one or more collations. If multiple collations are used, the collations need to be specified in a parenthesis. When only one collation is used, the parenthesis is optional.

    Collation is not supported by SQL++ for Server.

    Syntax

    Example 45. COLLATE Operator Syntax

    collate   = COLLATE _ ( collation | '(' collation ( _ collation )+ ')' )
collation = NO? (UNICODE | CASE | DIACRITICS)

    Arguments

    1. The available collation options are:

      • UNICODE: Conduct a Unicode comparison; the default is to do ASCII comparison.

      • CASE: Conduct case-sensitive comparison

      • DIACRITIC: Take accents and diacritics into account in the comparison; On by default.

      • NO: This can be used as a prefix to the other collations, to disable them. For example, use NOCASE to enable case-insensitive comparison.

    Example

    Example 46. COLLATE Operator Example

    SELECT contact
FROM crm.customer
WHERE contact.firstName = "fred" COLLATE UNICODE;

SELECT contact
FROM crm.customer
WHERE contact.firstName = "fred" COLLATE (UNICODE CASE);

SELECT firstName, lastName
FROM crm.customer
ORDER BY firstName COLLATE (UNICODE DIACRITIC), lastName COLLATE (UNICODE DIACRITIC);

    Conditional Operator

    Purpose

    The conditional (or CASE) operator evaluates conditional logic in a similar way to the IF/ELSE operator.

    Syntax

    Example 47. Conditional Operators Syntax

    case = CASE _ ( expression _ )?
       ( WHEN _ expression _ THEN _ expression _ )+
       ( ELSE _ expression _)?
       END

    Both Simple Case and Searched Case expressions are supported. The syntactic difference being that the Simple Case expression has an expression after the CASE keyword.

    1. Simple Case Expression

      • If the CASE expression is equal to the first WHEN expression, the result is the THEN expression.

      • Otherwise, any subsequent WHEN clauses are evaluated in the same way.

      • If no match is found, the result of the CASE expression is the ELSE expression, or NULL if no ELSE expression was provided.

    2. Searched Case Expression

      • If the first WHEN expression is TRUE, the result of this expression is its THEN expression.

      • Otherwise, subsequent WHEN clauses are evaluated in the same way.

      • If no WHEN clause evaluate to TRUE, then the result of the expression is the ELSE expression, or NULL if no ELSE expression was provided.

    Examples

    Example 48. Simple Case

    SELECT
  CASE state
    WHEN 'CA'
      THEN 'Local'
    ELSE 'Non-Local'
  END
FROM testScope.testCollection;

    Examples

    Example 49. Searched Case

    SELECT
  CASE
    WHEN shippedOn IS NOT NULL
      THEN 'SHIPPED'
    ELSE 'NOT-SHIPPED'
  END
FROM testScope.testCollection;

    Functions

    Purpose

    Functions provide specialised operations through a generalized syntax.

    Syntax

    Example 50. Functions Syntax

    The function syntax is the same as C-style language function syntax. It starts with the function name, followed by optional arguments inside parentheses.

    function      = functionName _? '(' ( _? expression ( _? ',' _? expression )* _? )? ')'
functionName  = IDENTIFIER

    Aggregation Functions

    Table 10. Aggregation Functions

    Function Description

    AVG(value)

    Returns the average of all numeric values in the group.

    COUNT(value)

    Returns the count of all values in the group.

    MIN(value)

    Returns the minimum numeric value in the group.

    MAX(value)

    Returns the maximum numeric value in the group.

    SUM(value)

    Returns the sum of all numeric values in the group.

    Array Functions

    Table 11. Array Functions

    Function Description

    ARRAY_AGG(value)

    Returns an array of the non-MISSING group values in the input expression, including NULL values.

    ARRAY_AVG(value)

    Returns the average of all non-NULL number values in the array; or NULL if there are none.

    ARRAY_CONTAINS(value)

    Returns TRUE if the value exists in the array; otherwise FALSE.

    ARRAY_COUNT(value)

    Returns the number of non-NULL values in the array.

    ARRAY_IFNULL(value)

    Returns the first non-NULL value in the array.

    ARRAY_MAX(value)

    Returns the largest non-NULL, non_MISSING value in the array.

    ARRAY_MIN(value)

    Returns the smallest non-NULL, non_MISSING value in the array.

    ARRAY_LENGTH(value)

    Returns the length of the array.

    ARRAY_SUM(value)

    Returns the sum of all non-NULL numeric value in the array.

    Conditional Functions

    Table 12. Conditional Functions

    Function Description

    IFMISSING(value, ...)

    Returns the first non-MISSING value, or NULL if all values are MISSING.

    IFMISSINGORNULL(value, ...)

    Returns the first non-NULL and non-MISSING value, or NULL if all values are NULL or MISSING.

    IFNULL(value, ...)

    Returns the first non-NULL, or NULL if all values are NULL.

    MISSINGIF(value, other)

    Returns MISSING when value = other; otherwise returns value.
    Returns MISSING if either or both expressions are MISSING.
    Returns NULL if either or both expressions are NULL.

    NULLIF(value, other)

    Returns NULL when value = other; otherwise returns value.
    Returns MISSING if either or both expressions are MISSING.
    Returns NULL if either or both expressions are NULL.

    Date and Time Functions

    Table 13. Date and Time Functions

    Function Description

    STR_TO_MILLIS(value)

    Returns the number of milliseconds since the unix epoch of the given ISO 8601 date input string.

    STR_TO_UTC(value)

    Returns the ISO 8601 UTC date time string of the given ISO 8601 date input string.

    MILLIS_TO_STR(value)

    Returns a ISO 8601 date time string in device local timezone of the given number of milliseconds since the unix epoch expression.

    MILLIS_TO_UTC(value)

    Returns the UTC ISO 8601 date time string of the given number of milliseconds since the unix epoch expression.

    Full Text Search Functions

    Table 14. FTS Functions

    Function Description Example

    MATCH(indexName, term) | Returns TRUE if term expression matches the FTS indexed document. indexName identifies the FTS index to search for matches. | WHERE MATCH(description, 'couchbase')`

    RANK(indexName)

    Returns a numeric value indicating how well the current query result matches the full-text query when performing the MATCH. indexName is an IDENTIFIER for the FTS index.

    WHERE MATCH(description, 'couchbase') ORDER BY RANK(description)

    Maths Functions

    Table 15. Maths Functions

    Function Description

    ABS(value)

    Returns the absolute value of a number.

    ACOS(value)

    Returns the arc cosine in radians.

    ASIN(value)

    Returns the arcsine in radians.

    ATAN(value)

    Returns the arctangent in radians.

    ATAN2(a, b)

    Returns the arctangent of a / b.

    CEIL(value)

    Returns the smallest integer not less than the number.

    COS(value)

    Returns the cosine of an angle in radians.

    DIV(a, b)

    Returns float division of a and b. Both a and b are cast to a double number before division. The returned result is always a double.

    DEGREES(value)

    Converts radians to degrees.

    E()

    Returns the e constant, which is the base of natural logarithms.

    EXP(value)

    Returns the natural exponential of a number.

    FLOOR(value)

    Returns largest integer not greater than the number.

    IDIV(a, b)

    Returns integer division of a and b.

    LN(value)

    Returns log base e.

    LOG(value)

    Returns log base 10.

    PI()

    Returns the pi constant.

    POWER(a, b)

    Returns a to the bth power.

    RADIANS(value)

    Converts degrees to radians.

    ROUND(value (, digits)?)

    Returns the rounded value to the given number of integer digits to the right of the decimal point (left if digits is negative). Digits are 0 if not given.

    The function uses Rounding Away From Zero convention to round midpoint values to the next number away from zero (so, for example, ROUND(1.75) returns 1.8 but ROUND(1.85) returns 1.9.

    ROUND_EVEN(value (, digits)?)

    Returns rounded value to the given number of integer digits to the right of the decimal point (left if digits is negative). Digits are 0 if not given.

    The function uses Rounding to Nearest Even (Banker’s Rounding) convention which rounds midpoint values to the nearest even number (for example, both ROUND_EVEN(1.75) and ROUND_EVEN(1.85) return 1.8).

    SIGN(value)

    Returns -1 for negative, 0 for zero, and 1 for positive numbers.

    SIN(value)

    Returns sine of an angle in radians.

    SQRT(value)

    Returns the square root.

    TAN(value)

    Returns tangent of an angle in radians.

    TRUNC(value (, digits)?)

    Returns a truncated number to the given number of integer digits to the right of the decimal point (left if digits is negative). Digits are 0 if not given.

    The behavior of the ROUND() function is different from SQL++ for Server ROUND(), which rounds the midpoint values using Rounding to Nearest Even convention.

    Pattern Searching Functions

    Table 16. Pattern Searching Functions

    Function Description

    REGEXP_CONTAINS(value, pattern)

    Returns TRUE if the string value contains any sequence that matches the regular expression pattern.

    REGEXP_LIKE(value, pattern)

    Return TRUE if the string value exactly matches the regular expression pattern.

    REGEXP_POSITION(value, pattern)

    Returns the first position of the occurrence of the regular expression pattern within the input string expression. Returns -1 if no match is found. Position counting starts from zero.

    REGEXP_REPLACE(value, pattern, repl [, n])

    Returns a new string with occurrences of pattern replaced with repl. If n is given, at the most n replacements are performed. If n is not given, all matching occurrences are replaced.

    String Functions

    Table 17. String Functions

    Function Description

    CONTAINS(value, substring)

    Returns TRUE if the substring exists within the input string, otherwise returns FALSE.

    LENGTH(value)

    Returns the length of a string. The length is defined as the number of characters within the string.

    LOWER(value)

    Returns the lower-case string of the input string.

    LTRIM(value)

    Returns the string with all leading whitespace characters removed.

    RTRIM(value)

    Returns the string with all trailing whitespace characters removed.

    TRIM(value)

    Returns the string with all leading and trailing whitespace characters removed.

    UPPER(value)

    Returns the upper-case string of the input string.

    Type Checking Functions

    Table 18. Type Checking Functions

    Function Description

    ISARRAY(value)

    Returns TRUE if value is an array, otherwise returns MISSING, NULL or FALSE.

    ISATOM(value)

    Returns TRUE if value is a boolean, number, or string, otherwise returns MISSING, NULL or FALSE.

    ISBOOLEAN(value)

    Returns TRUE if value is a boolean, otherwise returns MISSING, NULL or FALSE.

    ISNUMBER(value)

    Returns TRUE if value is a number, otherwise returns MISSING, NULL or FALSE.

    ISOBJECT(value)

    Returns TRUE if value is an object (dictionary), otherwise returns MISSING, NULL or FALSE.

    ISSTRING(value)

    Returns TRUE if value is a string, otherwise returns MISSING, NULL or FALSE.

    TYPE(value)

    Returns one of the following strings, based on the value of value:
    • "missing"
    • "null"
    • "boolean"
    • "number"
    • "string"
    • "array"
    • "object"
    • "binary"

    Type Conversion Functionsunctions

    Table 19. Type Conversion Functions

    Function Description

    TOARRAY(value)

    Returns MISSING if the value is MISSING.
    Returns NULL if the value is NULL.
    Returns an array value as is.
    Returns all other values wrapped in an array.

    TOATOM(value)

    Returns MISSING if the value is MISSING.
    Returns NULL if the value is NULL.
    Returns an array of a single item if the value is an array.
    Returns an object of a single key/value pair if the value is an object.
    Returns a boolean, number, or string value as is.
    Returns NULL for all other values.

    TOBOOLEAN(value)

    Returns MISSING if the value is MISSING.
    Returns NULL if the value is NULL.
    Returns FALSE if the value is FALSE.
    Returns FALSE if the value is 0 or NaN.
    Returns FALSE if the value is an empty string, array, and object.
    Return TRUE for all other values.

    TONUMBER(value)

    Returns MISSING if the value is MISSING.
    Returns NULL if the value is NULL.
    Returns 0 if the value is FALSE.
    Returns 1 if the value is TRUE.
    Returns a number value as is.
    Parses a string value in to a number.
    Returns NULL for all other values.

    TOOBJECT(value)

    Returns MISSING if the value is MISSING.
    Returns NULL if the value is NULL.
    Returns an object value as is.
    Returns an empty object for all other values.

    TOSTRING(value)

    Returns MISSING if the value is MISSING.
    Returns NULL if the value is NULL.
    Returns "false" if the value is FALSE.
    Returns "true" if the value is TRUE.
    Returns a string representation of a number value.
    Returns a string value as is.
    Returns NULL for all other values.

    QueryBuilder Differences

    SQL++ for Mobile queries support all QueryBuilder features. See <<,Table 20>> for the features supported by SQL++ for Mobile but not by QueryBuilder.

    Table 20. QueryBuilder Differences

    Category Components

    Conditional Operator

    CASE(WHEN ... THEN ... ELSE ...)

    Array Functions

    ARRAY_AGG, ARRAY_AVG, ARRAY_COUNT, ARRAY_IFNULL, ARRAY_MAX, ARRAY_MIN, ARRAY_SUM

    Conditional Functions

    IFMISSING, IFMISSINGORNULL, IFNULL, MISSINGIF, NULLIF, MATCH, RANK, DIV, IDIV, ROUND_EVEN

    Pattern Matching Functions

    REGEXP_CONTAINS, REGEXP_LIKE, REGEXP_POSITION, REGEXP_REPLACE

    Type Checking Functions

    ISARRAY, ISATOM, ISBOOLEAN, ISNUMBER, ISOBJECT, ISSTRING, TYPE

    Type Conversion Functions

    TOARRAY, TOATOM, TOBOOLEAN, TONUMBER, TOOBJECT, TOSTRING

    Query Parameters

    You can provide runtime parameters to your SQL++ query to make it more flexible. To specify substitutable parameters within your query string prefix the name with $ - see: Example 51.

    Example 51. Running a SQL++ Query

    You can provide runtime parameters to your SQL++ query to make it more flexible. To specify substitutable parameters within your query string prefix the name with $ - see: Example 51.

    const query = await database.createQuery(
  'SELECT META().id AS docId FROM hotel WHERE country = $country'
);

const params = new Parameters();
params.setString('country','France')
query.parameters = params;
const resultSet = await query.execute();

    1. Define a parameter placeholder $country.

    2. Set the value of the country parameter.