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OR

Operator Description

OR,|| Logical operator is used as logical or operations. When both operands are not null, the result is true if the operand is also non-zero, otherwise false; for the NULL operand, if the other operand is not zero, then the result is true, otherwise NULL; if both operands are not NULL, the result is NULL.

Grammar Structure

> SELECT column_1 OR column_2 FROM table_name;

Example

mysql> select 1 or 1;
+---------+
| 1 or 1 |
+---------+
| true |
+---------+
1 row in set (0.01 sec)

mysql> select 1 or 0;
+---------+
| 1 or 0 |
+---------+
| true |
+---------+
1 row in set (0.00 sec)

mysql> select 0 or 0;
+---------+
| 0 or 0 |
+---------+
| false |
+---------+
1 row in set (0.01 sec)

mysql> select 0 or null;
+---------------+
| 0 or null |
+---------------+
| NULL |
+---------------+
1 row in set (0.00 sec)

mysql> select 1 or null;
+---------------+
| 1 or null |
+---------------+
| true |
+---------------+
1 row in set (0.00 sec)

create table t1 (a boolean,b bool);
insert into t1 values ​​(0,1),(true,false),(true,1),(0,false),(NULL,NULL);

mysql> select a or b from t1;
+---------+
| a or b |
+---------+
| true |
| true |
| true |
| false |
| NULL |
+---------+
5 rows in set (0.00 sec)