通过

==（双等号）运算符

适用于：勾选“是” Databricks SQL 勾选“是” Databricks Runtime

如果 true 等于 expr1，则返回 expr2；否则返回 false。 此函数是等号运算符=的同义词。 使用 equal_null 将 NULL 视为可比值。

语法

expr1 == expr2

参数

  • expr1：任何可比较类型的表达式。
  • expr2：与 expr1 共享最不常见类型的表达式。

返回

BOOLEAN。

示例

> SELECT 2 == 2;
 true

> SELECT 1 == '1';
 true

> SELECT true == NULL;
 NULL

> SELECT NULL == NULL;
 NULL

-- By default string comparisons are trailing blank 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

 -- By default string comparisons are trailing space sensitive
-- This can be overridden by using the COLLATE clause
> 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