# IF expression
<a name="IF"></a>

The IF conditional function returns one of two values based on a condition. 

This function is a common control flow statement used in SQL to make decisions and return different values based on the evaluation of a condition. It's useful for implementing simple if-else logic within a query.

## Syntax
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```
if(expr1, expr2, expr3) 
```

## Arguments
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*expr1*  
The condition or expression that is evaluated. If it is `true`, the function will return the value of *expr2*. If *expr1* is `false`, the function will return the value of *expr3*.

*expr2*  
The expression that is evaluated and returned if *expr1* is `true`.

*expr3*  
The expression that is evaluated and returned if *expr1* is `false`.

## Returns
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If `expr1` evaluates to `true`, then returns `expr2`; otherwise returns `expr3`.

## Example
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The following example uses the `if()` function to return one of two values based on a condition. The condition being evaluated is `1 < 2`, which is `true`, so the first value `'a'` is returned.

```
SELECT if(1 < 2, 'a', 'b');
 a]
```