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Not equal <> != operator on NULL

2019-12-24 13:53:02  阅读:272  来源: 互联网

标签:compare null equal value say operator NULL my


https://stackoverflow.com/questions/5658457/not-equal-operator-on-null

<> is Standard SQL-92; != is its equivalent. Both evaluate for values, which NULL is not -- NULL is a placeholder to say there is the absence of a value.

Which is why you can only use IS NULL/IS NOT NULL as predicates for such situations.

This behavior is not specific to SQL Server. All standards-compliant SQL dialects work the same way.

Note: To compare if your value is not null, you use IS NOT NULL, while to compare with not null value, you use <> 'YOUR_VALUE'. I can't say if my value equals or not equals to NULL, but I can say if my value is NULL or NOT NULL. I can compare if my value is something other than NULL. 

标签:compare,null,equal,value,say,operator,NULL,my
来源: https://www.cnblogs.com/chucklu/p/12091082.html

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