versioned_docs/version-2.1/sql-manual/sql-functions/aggregate-functions/array-agg.md

---
{
    "title": "ARRAY_AGG",
    "language": "en"
}
---

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## ARRAY_AGG

### description

#### Syntax

`ARRAY_AGG(col)`

Concatenation of values in a column (including the null value) into an array can be used for multiple rows to one row (row to column).

### notice

- The order of the elements in an array is not guaranteed.
- Returns the array generated by the transformation. The element type in the array is the same as the col type.

### example

```sql
mysql> select * from test_doris_array_agg;

+------+------+

| c1   | c2   |

+------+------+

|    1 | a    |

|    1 | b    |

|    2 | c    |

|    2 | NULL |

|    3 | NULL |

+------+------+

mysql> select c1, array_agg(c2) from test_doris_array_agg group by c1;

+------+-----------------+

| c1   | array_agg(`c2`) |

+------+-----------------+

|    1 | ["a","b"]       |

|    2 | [NULL,"c"]      |

|    3 | [NULL]          |

+------+-----------------+
```

### keywords

ARRAY_AGG