<li> <p>NOT, ! </p> <p> Logical NOT. Evaluates to 1 if the operand is 0, to 0 if the operand is non-zero, and NOT NULL returns NULL. </p> <b class='title'>DQL condition :</b> NOT 10<br \> -> 0<br \> <b class='title'>DQL condition :</b> NOT 0<br \> -> 1<br \> <b class='title'>DQL condition :</b> NOT NULL<br \> -> NULL<br \> <b class='title'>DQL condition :</b> ! (1+1)<br \> -> 0<br \> <b class='title'>DQL condition :</b> ! 1+1<br \> -> 1<br \> </pre> <p> The last example produces 1 because the expression evaluates the same way as (!1)+1. </p> </li> <li> <p><a name="function_and"></a> <a class="indexterm" name="id2965271"></a> <a class="indexterm" name="id2965283"></a> AND </p> <p> Logical AND. Evaluates to 1 if all operands are non-zero and not NULL, to 0 if one or more operands are 0, otherwise NULL is returned. </p> <b class='title'>DQL condition :</b> 1 AND 1<br \> -> 1<br \> <b class='title'>DQL condition :</b> 1 AND 0<br \> -> 0<br \> <b class='title'>DQL condition :</b> 1 AND NULL<br \> -> NULL<br \> <b class='title'>DQL condition :</b> 0 AND NULL<br \> -> 0<br \> <b class='title'>DQL condition :</b> NULL AND 0<br \> -> 0<br \> </pre> </li> <li> OR </p> <p> Logical OR. When both operands are non-NULL, the result is 1 if any operand is non-zero, and 0 otherwise. With a NULL operand, the result is 1 if the other operand is non-zero, and NULL otherwise. If both operands are NULL, the result is NULL. </p> <b class='title'>DQL condition :</b> 1 OR 1<br \> -> 1<br \> <b class='title'>DQL condition :</b> 1 OR 0<br \> -> 1<br \> <b class='title'>DQL condition :</b> 0 OR 0<br \> -> 0<br \> <b class='title'>DQL condition :</b> 0 OR NULL<br \> -> NULL<br \> <b class='title'>DQL condition :</b> 1 OR NULL<br \> -> 1<br \> </pre> </li> <li> <p><a name="function_xor"></a> <a class="indexterm" name="id2965520"></a> XOR </p> <p> Logical XOR. Returns NULL if either operand is NULL. For non-NULL operands, evaluates to 1 if an odd number of operands is non-zero, otherwise 0 is returned. </p> <b class='title'>DQL condition :</b> 1 XOR 1<br \> -> 0<br \> <b class='title'>DQL condition :</b> 1 XOR 0<br \> -> 1<br \> <b class='title'>DQL condition :</b> 1 XOR NULL<br \> -> NULL<br \> <b class='title'>DQL condition :</b> 1 XOR 1 XOR 1<br \> -> 1<br \> </pre> <p> a XOR b is mathematically equal to (a AND (NOT b)) OR ((NOT a) and b). </p> </li> </ul>