In MySQL, the COALESCE() operator returns the first non-NULL value in the list, or NULL if there are no non-NULL values.
Author: Ian
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In SQL Server, if you’re getting error Msg 4127 that reads “At least one of the arguments to COALESCE must be an expression that is not the NULL constant”, it’s probably because all of your arguments to the COALESCE() expression are the NULL constant.
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In SQL Server, the COALESCE() expression returns its first non-null argument.
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