MySQL comparison with null value

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In MySQL, NULL is considered as a ‘missing, unknown value’, as opposed to no value. Take a look at this MySQL Reference on NULL.

Any arithmetic comparison with NULL does not return true or false, but returns NULL instead., So, NULL != 'C' returns NULL, as opposed to returning true.

Any arithmetic comparison with ‘NULL’ will return false. To check this in SQL: 

SELECT IF(NULL=123,'true','false')

To check NULL values we need to use IS NULL & IS NOT NULL operator.

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