# Flow Control Functions
+ **`CASE`** expression
+ **`NULLIF()`** function
+ **`IFNULL()`** function
+ **`IF()`** function

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- TiDB supports the use of all flow control functions provided in MySQL 5.7
  - **`CASE`**  Case operator
  - **`IF()`**  Build if/else
  - **`IFNULL()`**  Build Null if/else
  - **`NULLIF()`**  If expr1 = expr2, return NULL