# **=**

## **Operator Description**

The `=` operator is used to assign values in the following cases:

- In the `SET` statement, `=` is regarded as an assignment operator, that is, the user variable to the left of the operator `=` takes the value to its right. The value to the right can be a text value, another variable that stores the value, or any legal expression that produces a scalar value, or it can also include the result of the query (provided that the value is a scalar value). Multiple assignments can be performed in the same `SET` statement.

- In the `SET` clause of the `UPDATE` statement, `=` also acts as an assignment operator. You can make multiple assignments in the same `SET` clause of a `UPDATE` statement.

- In other cases, `=` is used as the comparison operator.

## **Grammar Structure**

```sql
SELECT column1, column2, ...
FROM table_name
WHERE columnN = value1;
```

## **Example**

```text
create table t1 (a bigint(3), b bigint(5) primary key);
insert into t1 VALUES (1,1),(1,2);
update t1 set a=2 where a=1 limit 1;

mysql> select * from t1;
+------+------+
| a | b |
+------+------+
| 2 | 1 |
| 1 | 2 |
+------+------+
2 rows in set (0.00 sec)
```