ABAP Keyword Documentation → ABAP − Reference → Program Flow Logic → Expressions and Functions for Conditions → log_exp - Logical Expressions → log_exp - Boolean Operators and Parentheses

# log_exp - NOT

Other versions:
7.31 | 7.40 | **7.54**

## Syntax

```
... NOT log_exp ...
```

### Effect

The negation of a logical expression `log_exp`

using `NOT`

creates a new logical expression that is false if the logical expression `log_exp`

is true and vice versa.

Notes

- The operator
`NOT`

is a stronger join than`AND`

,`OR`

, and`EQUIV`

.

- The Boolean operator
`NOT`

must not be confused with the addition`NOT`

of the relational operators`BETWEEN`

,`IN`

, and the predicate operator`IS`

. The following syntax is one possible example:

`... NOT operand NOT IN range_tab ...`

`NOT`

is a Boolean operator that negates a comparison expression.
The second `NOT`

is a part of the comparison expression with the relational operator `IN`

. This is made clear using parentheses around the comparison expression:
`... NOT ( operand NOT IN range_tab ) ...`

Example

Exit the current processing block if `sy-subrc`

does not have the value 0.

```
IF NOT sy-subrc = 0.
RETURN.
ENDIF.
```