# **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**

```sql
SELECT column_1 OR column_2 FROM table_name;
```

## **Example**

```text
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)
```

```text
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)
```