# Case Conversion Functions

+ **`LOWER()/LCASE()`** and **`UPPER()/UCASE()`**: Return a string, and the result is changed to lowercase or uppercase
+ For example:
```
tidb> SELECT LOWER('TiDB'), UPPER('TiKV');
+---------------+---------------+
| LOWER('TiDB') | UPPER('TiKV') |
+---------------+---------------+
| tidb          | TIKV          |
+---------------+---------------+
1 row in set (0.00 sec)
```

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- LOWER () /LCASE () return lowercase
- UPPER () /UCASE () return uppercase