Type Functions
- reference
Type functions perform operations that check or convert expressions.
If any arguments to any of the following functions are MISSING then the result is also MISSING (i.e.
no result is returned).
Similarly, if any of the arguments passed to the functions are NULL or are of the wrong type (e.g.
an integer instead of a string), then NULL is returned as the result.
|
ISARRAY(expression)
Examples
SELECT ISARRAY(true) AS `boolean`,
ISARRAY(MISSING) AS `missing`,
ISARRAY(NULL) AS `null`,
ISARRAY(123) AS `number`,
ISARRAY("hello world") AS `string`,
ISARRAY([1, 2, 3]) AS `array`,
ISARRAY({"hello": "world"}) AS `object`;
[
{
"array": true,
"boolean": false,
"null": null,
"number": false,
"object": false,
"string": false
}
]
ISATOM(expression)
Return Value
Returns True if expression is a Boolean, number, or string, otherwise returns MISSING, NULL or false.
Examples
SELECT ISATOM(true) AS `boolean`,
ISATOM(MISSING) AS `missing`,
ISATOM(NULL) AS `null`,
ISATOM(123) AS `number`,
ISATOM("hello world") AS `string`,
ISATOM([1, 2, 3]) AS `array`,
ISATOM({"hello": "world"}) AS `object`;
[
{
"array": false,
"boolean": true,
"null": null,
"number": true,
"object": false,
"string": true
}
]
ISBOOLEAN(expression)
Examples
SELECT ISBOOLEAN(true) AS `boolean`,
ISBOOLEAN(MISSING) AS `missing`,
ISBOOLEAN(NULL) AS `null`,
ISBOOLEAN(123) AS `number`,
ISBOOLEAN("hello world") AS `string`,
ISBOOLEAN([1, 2, 3]) AS `array`,
ISBOOLEAN({"hello": "world"}) AS `object`;
[
{
"array": false,
"boolean": true,
"null": null,
"number": false,
"object": false,
"string": false
}
]
ISNUMBER(expression)
Examples
SELECT ISNUMBER(true) AS `boolean`,
ISNUMBER(MISSING) AS `missing`,
ISNUMBER(NULL) AS `null`,
ISNUMBER(123) AS `number`,
ISNUMBER("hello world") AS `string`,
ISNUMBER([1, 2, 3]) AS `array`,
ISNUMBER({"hello": "world"}) AS `object`;
[
{
"array": false,
"boolean": false,
"null": null,
"number": true,
"object": false,
"string": false
}
]
ISOBJECT(expression)
Examples
SELECT ISOBJECT(true) AS `boolean`,
ISOBJECT(MISSING) AS `missing`,
ISOBJECT(NULL) AS `null`,
ISOBJECT(123) AS `number`,
ISOBJECT("hello world") AS `string`,
ISOBJECT([1, 2, 3]) AS `array`,
ISOBJECT({"hello": "world"}) AS `object`;
[
{
"array": false,
"boolean": false,
"null": null,
"number": false,
"object": true,
"string": false
}
]
ISSTRING(expression)
Examples
SELECT ISSTRING(true) AS `boolean`,
ISSTRING(MISSING) AS `missing`,
ISSTRING(NULL) AS `null`,
ISSTRING(123) AS `number`,
ISSTRING("hello world") AS `string`,
ISSTRING([1, 2, 3]) AS `array`,
ISSTRING({"hello": "world"}) AS `object`;
[
{
"array": false,
"boolean": false,
"null": null,
"number": false,
"object": false,
"string": true
}
]
ISVECTOR(vector
, dimension
, format
)
Description
Checks if the supplied expression is an array of floating point numbers with the specified number of dimensions. This can be used to determine whether a field contains a vector value.
Arguments
- vector
-
An array of floating point numbers, or any SQL++ expression that evaluates to an array of floating point numbers.
- dimension
-
An integer representing the number of dimensions.
- format
-
A string. This argument must always be present and must have the value
"float32"
.
Return Value
Returns true
if the expression is an array of floating point numbers with the specified number of dimensions.
Examples
To try the examples in this section, you must install the rgb
and rgb-questions
collections from the supplied vector sample, as described in Prerequisites.
SELECT ISVECTOR([1, 2, 3, 4], 4, "float32") as vector,
ISVECTOR([1, 2, 3, 4], 3, "float32") as wrong_dimension,
ISVECTOR(["a", "b", "c", "d"], 4, "float32") as wrong_values;
[
{
"vector": true,
"wrong_dimension": false,
"wrong_values": false
}
]
Check whether the specified fields in the rgb
collection contain vector values.
SELECT ISVECTOR(description, 1, "float32") AS description,
ISVECTOR(colorvect_l2, 3, "float32") AS colorvect_l2,
ISVECTOR(embedding_vector_dot, 1536, "float32") AS embedding_vector_dot
FROM `vector-sample`.color.rgb LIMIT 1;
[{
"description": false,
"colorvect_l2": true,
"embedding_vector_dot": true
}]
The results show that the description
field is not a vector field. The colorvect_l2
and embedding_vector_dot
fields are vector fields, with the specified number of dimensions.
TYPE(expression)
Return Value
Returns one of the following strings, based on the value of expression:
-
"missing"
-
"null"
-
"boolean"
-
"number"
-
"string"
-
"array"
-
"object"
-
"binary"
Examples
SELECT TYPE(true) AS `boolean`,
TYPE(MISSING) AS `missing`,
TYPE(NULL) AS `null`,
TYPE(123) AS `number`,
TYPE("hello world") AS `string`,
TYPE([1, 2, 3]) AS `array`,
TYPE({"hello": "world"}) AS `object`;
[
{
"array": "array",
"boolean": "boolean",
"missing": "missing",
"null": "null",
"number": "number",
"object": "object",
"string": "string"
}
]
TOARRAY(expression)
Return Value
Returns one of the following strings, based on the value of expression:
Returns array as follows:
-
MISSING is MISSING.
-
NULL is NULL.
-
Arrays are themselves.
-
All other values are wrapped in an array.
Examples
SELECT TOARRAY(true) AS `boolean`,
TOARRAY(MISSING) AS `missing`,
TOARRAY(NULL) AS `null`,
TOARRAY(123) AS `number`,
TOARRAY("hello world") AS `string`,
TOARRAY([1, 2, 3]) AS `array`,
TOARRAY({"hello": "world"}) AS `object`;
[
{
"array": [
1,
2,
3
],
"boolean": [
true
],
"null": null,
"number": [
123
],
"object": [
{
"hello": "world"
}
],
"string": [
"hello world"
]
}
]
TOATOM(expression)
Return Value
Returns atomic value as follows:
-
MISSING is MISSING.
-
NULL is NULL.
-
Arrays of length 1 are the result of TOATOM() on their single element.
-
Objects of length 1 are the result of TOATOM() on their single value.
-
Booleans, numbers, and strings are themselves.
-
All other values are NULL.
Examples
SELECT TOATOM(true) AS `boolean`,
TOATOM(MISSING) AS `missing`,
TOATOM(NULL) AS `null`,
TOATOM(123) AS `number`,
TOATOM("hello world") AS `string`,
TOATOM([1, 2, 3]) AS `array`,
TOATOM({"hello": "world"}) AS `object`;
[
{
"array": null,
"boolean": true,
"null": null,
"number": 123,
"object": "world",
"string": "hello world"
}
]
TOBOOLEAN(expression)
Return Value
Returns Boolean as follows:
-
MISSING is MISSING.
-
NULL is NULL.
-
False is false.
-
Numbers +0, -0, and NaN are false.
-
Empty strings, arrays, and objects are false.
-
All other values are true.
Examples
SELECT TOBOOLEAN(true) AS `boolean`,
TOBOOLEAN(MISSING) AS `missing`,
TOBOOLEAN(NULL) AS `null`,
TOBOOLEAN(123) AS `number`,
TOBOOLEAN("hello world") AS `string`,
TOBOOLEAN([1, 2, 3]) AS `array`,
TOBOOLEAN({"hello": "world"}) AS `object`;
[
{
"array": true,
"boolean": true,
"null": null,
"number": true,
"object": true,
"string": true
}
]
TONUMBER(expression [, string-expression])
Arguments
- expression
-
[Required] The expression to convert.
- string-expression
-
[Optional] Characters to strip from the input expression before conversion, if the input expression is a string.
Return Value
Returns number as follows:
-
MISSING is MISSING.
-
NULL is NULL.
-
False is 0.
-
True is 1.
-
Numbers are themselves.
-
Strings that parse as numbers are those numbers.
-
All other values are NULL.
If string-expression
is supplied, and the input expression is a string, then the following operations are carried out before conversion:
-
All whitespace is stripped from the input expression string.
-
All characters listed in
string-expression
are stripped from the input expression string. -
If a decimal comma is detected, it is replaced with a decimal point — all other points must be removed from the input expression string.
If string-expression
is not supplied, then the input expression string is parsed as-is.
Examples
SELECT TONUMBER(true) AS `boolean`,
TONUMBER(MISSING) AS `missing`,
TONUMBER(NULL) AS `null`,
TONUMBER(123) AS `number`,
TONUMBER("hello world") AS `string`,
TONUMBER([1, 2, 3]) AS `array`,
TONUMBER({"hello": "world"}) AS `object`;
[
{
"array": null,
"boolean": 1,
"null": null,
"number": 123,
"object": null,
"string": null
}
]
SELECT TONUMBER("AU$123456.78", "AU$") AS `aud`,
TONUMBER("€123.456,78 ", "€.") AS `eur`,
TONUMBER("$ 123,456.78", "$,") AS `usd`,
TONUMBER("¥123 456 789.00", "¥") AS `yen`;
[
{
"aud": 123456.78,
"eur": 123456.78,
"usd": 123456.78,
"yen": 123456789
}
]
TOOBJECT(expression)
Return Value
Returns object as follows:
-
MISSING is MISSING.
-
NULL is NULL.
-
Objects are themselves.
-
All other values are the empty object.
Examples
SELECT TOOBJECT(true) AS `boolean`,
TOOBJECT(MISSING) AS `missing`,
TOOBJECT(NULL) AS `null`,
TOOBJECT(123) AS `number`,
TOOBJECT("hello world") AS `string`,
TOOBJECT([1, 2, 3]) AS `array`,
TOOBJECT({"hello": "world"}) AS `object`;
[
{
"array": {},
"boolean": {},
"null": null,
"number": {},
"object": {
"hello": "world"
},
"string": {}
}
]
TOSTRING(expression)
Return Value
Returns string as follows:
-
MISSING is MISSING.
-
NULL is NULL.
-
False is "false".
-
True is "true".
-
Numbers are their string representation.
-
Strings are themselves.
-
All other values are NULL.
Examples
SELECT TOSTRING(true) AS `boolean`,
TOSTRING(MISSING) AS `missing`,
TOSTRING(NULL) AS `null`,
TOSTRING(123) AS `number`,
TOSTRING("hello world") AS `string`,
TOSTRING([1, 2, 3]) AS `array`,
TOSTRING({"hello": "world"}) AS `object`;
[
{
"array": null,
"boolean": "true",
"null": null,
"number": "123",
"object": null,
"string": "hello world"
}
]