---
{
    "title": "coalesce",
    "language": "zh-CN"
}
---

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# coalesce
## description
### Syntax

`VARCHAR coalesce(VARCHAR, ...)`
`...`
`INT coalesce(INT, ...)`

`coalesce`函数会返回第一个非NULL的值，若全部为NULL，则返回NULL

## example

```
MySQL> select coalesce(1,null,2);
+----------------------+
| coalesce(1, NULL, 2) |
+----------------------+
|                    1 |
+----------------------+

MySQL> select coalesce(null,"asd",1);
+--------------------------+
| coalesce(NULL, 'asd', 1) |
+--------------------------+
| asd                      |
+--------------------------+

MySQL> select coalesce(null,null,null);
+----------------------------+
| coalesce(NULL, NULL, NULL) |
+----------------------------+
|                       NULL |
+----------------------------+

```
## keyword
coalesce