| --- | |
| { | |
| "title": "ARRAY_AGG", | |
| "language": "en", | |
| "description": "Concatenates the values (including null values) in a column into an array, which can be used for pivoting rows into columns." | |
| } | |
| --- | |
| ## Description | |
| Concatenates the values (including null values) in a column into an array, which can be used for pivoting rows into columns. | |
| ## Syntax | |
| ```sql | |
| ARRAY_AGG(<col>) | |
| ``` | |
| ## Parameters | |
| | Parameter | Description | | |
| | -- | -- | | |
| | `<col>` | An expression that determines the values to be placed into the array. Supported types: Bool, TinyInt, SmallInt, Integer, BigInt, LargeInt, Float, Double, Decimal, Date, Datetime, TimestampNs, Timestamptz, IPV4, IPV6, UUID, String, Array, Map, Struct. | | |
| ## Return Value | |
| Returns a value of ARRAY type.Special cases: | |
| - The order of elements in the array is not guaranteed. | |
| - Returns the array generated by the conversion. The element type in the array is consistent with the type of col. | |
| ## Example | |
| ```sql | |
| -- setup | |
| CREATE TABLE test_doris_array_agg ( | |
| c1 INT, | |
| c2 INT | |
| ) DISTRIBUTED BY HASH(c1) BUCKETS 1 | |
| PROPERTIES ("replication_num" = "1"); | |
| INSERT INTO test_doris_array_agg VALUES (1, 10), (1, 20), (1, 30), (2, 100), (2, 200), (3, NULL); | |
| ``` | |
| ```sql | |
| select c1, array_agg(c2) from test_doris_array_agg group by c1; | |
| ``` | |
| ```text | |
| +------+---------------+ | |
| | c1 | array_agg(c2) | | |
| +------+---------------+ | |
| | 1 | [10, 20, 30] | | |
| | 2 | [100, 200] | | |
| | 3 | [null] | | |
| +------+---------------+ | |
| ``` | |
| ```sql | |
| select array_agg(c2) from test_doris_array_agg where c1 is null; | |
| ``` | |
| ```text | |
| +---------------+ | |
| | array_agg(c2) | | |
| +---------------+ | |
| | [] | | |
| +---------------+ | |
| ``` |