# Reverse, Concat
__*CONCAT function*__
__*CANCAT_WS function*__
__*REVERSE function*__
+ **`REVERSE()`**: Returns a string with the characters in reverse order
+ **`CONCAT(), CONCAT_WS()`**: Concatenates the given parameters into a string
+ For example: 
  + **`SELECT REVERSE('placeholder'), CONCAT('hello ','world'), CONCAT_WS(':','pingcap','tidb','training');`**  
```
tidb> SELECT REVERSE('placeholder'), CONCAT('hello ','world'), CONCAT_WS('~!@:@!~','pingcap','cmg','pe');
+------------------------+--------------------------+-------------------------------------+
| REVERSE('placeholder') | CONCAT('hello ','world') | CONCAT_WS(':','pingcap','cmg','pe') |
+------------------------+--------------------------+-------------------------------------+
| redlohecalp            | hello world              | pingcap:cmg:pe                      |
+------------------------+--------------------------+-------------------------------------+
1 row in set (0.00 sec)
```

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- CONCAT () return the concatenated string
- CONCAT_WS () return a string concatenated by a delimiter