# Control Flow Functions

- [CASE OPERATOR](https://mariadb.com/docs/server/reference/sql-functions/control-flow-functions/case-operator.md): Implement conditional logic in SQL queries. This operator evaluates conditions and returns a specific value when the first true condition is met.
- [DECODE\_ORACLE](https://mariadb.com/docs/server/reference/sql-functions/control-flow-functions/decode_oracle.md): Compare a value against a list of conditions. This Oracle-compatible function returns a corresponding result when a match is found, or a default value otherwise.
- [IF Function](https://mariadb.com/docs/server/reference/sql-functions/control-flow-functions/if-function.md): Complete IF() function reference: IF(expr1,expr2,expr3) conditional syntax, TRUE/NULL evaluation rules, return type context (numeric/string), and examples.
- [IFNULL](https://mariadb.com/docs/server/reference/sql-functions/control-flow-functions/ifnull.md): Replace NULL values with a fallback. This function returns the first argument if it's not NULL; otherwise, it returns the specified replacement value.
- [NULLIF](https://mariadb.com/docs/server/reference/sql-functions/control-flow-functions/nullif.md): Compare two expressions and return NULL if they are equal. If the expressions differ, the function returns the first expression.
- [NVL](https://mariadb.com/docs/server/reference/sql-functions/control-flow-functions/nvl.md): Synonym for IFNULL. This Oracle-compatible function returns the first argument if it is not NULL, or the second argument if the first is NULL.
- [NVL2](https://mariadb.com/docs/server/reference/sql-functions/control-flow-functions/nvl2.md): Return values based on NULL status. This function returns the second argument if the first is not NULL, and the third argument if the first is NULL.


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