> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/reference/sql-structure/operators/comparison-operators/null-safe-equal.md).

# <=>

## Syntax

```bnf
<=>
```

## Description

`NULL`-safe equal operator. It performs an equality comparison like the [= operator](/docs/server/reference/sql-structure/operators/comparison-operators/equal.md), but returns `1` rather than `NULL` if both operands are `NULL`, and `0` rather than `NULL` if one operand is `NULL`.

`a <=> b` is equivalent to `a = b OR (a IS NULL AND b IS NULL)`.

When used in row comparisons, these two queries return the same results:

```sql
SELECT (t1.a, t1.b) <=> (t2.x, t2.y) 
FROM t1 INNER JOIN t2;

SELECT (t1.a <=> t2.x) AND (t1.b <=> t2.y)
FROM t1 INNER JOIN t2;
```

See also [NULL Values in MariaDB](/docs/server/reference/data-types/null-values.md).

## Examples

```sql
SELECT 1 <=> 1, NULL <=> NULL, 1 <=> NULL;
+---------+---------------+------------+
| 1 <=> 1 | NULL <=> NULL | 1 <=> NULL |
+---------+---------------+------------+
|       1 |             1 |          0 |
+---------+---------------+------------+

SELECT 1 = 1, NULL = NULL, 1 = NULL;
+-------+-------------+----------+
| 1 = 1 | NULL = NULL | 1 = NULL |
+-------+-------------+----------+
|     1 |        NULL |     NULL |
+-------+-------------+----------+
```

## See Also

* [Operator Precedence](/docs/server/reference/sql-structure/operators/operator-precedence.md)

<sub>*This page is licensed: GPLv2, originally from*</sub> [<sub>*fill\_help\_tables.sql*</sub>](https://github.com/MariaDB/server/blob/main/scripts/fill_help_tables.sql)

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