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<=> (lt eq gt sign) operator

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Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime

Returns the same result as the EQUAL(=) for non-null operands, but returns true if both are NULL, false if one of the them is NULL. This operator is a synonym for expr1 is not distinct from expr2.

Syntax

expr1 <=> expr2

Arguments

  • expr1: An expression of a comparable type.
  • expr2: An expression that shares a least common type with expr1.

Returns

A BOOLEAN.

Examples

> SELECT 2 <=> 2;
 true
> SELECT 1 <=> '1';
 true
> SELECT true <=> NULL;
 false
> SELECT NULL <=> NULL;
 true

-- By default string comparisons are trailing space sensitive
-- This can be overridden by using the COLLATE clause
> SELECT 'hello' <=> 'hello  ' AS default,
         'hello' <=> 'hello  ' COLLATE UTF8_BINARY AS utf8_binary,
         'hello' <=> 'hello  ' COLLATE UTF8_BINARY_RTRIM AS rtrim;
 default utf8_binary rtrim
 ------- ----------- -----
 false   false       true

 -- String comparisons are trailing space sensitive by default
-- Use the COLLATE clause to override the default
> SELECT 'world  ' <=> 'world     ' AS default,
         'world  ' <=> 'world     ' COLLATE UTF8_BINARY AS utf8_binary,
         'world  ' <=> 'world     ' COLLATE UTF8_BINARY_RTRIM AS rtrim;
 default utf8_binary rtrim
 ------- ----------- -----
 false   false       true