Difference between NVL,NVL2, NULLIF and COALESCE

NVL function will check whether the first input parameter is null, if first input parameter is null then the function returns the second parameter value as output.

NVL2 function will check the first parameter, and return second parameter if the first parameter is not null, otherwise returns third parameter.

NULLIF will compare the input parameters ( first and second parameter ), and returns NULL of both are same, otherwise returns the first parameter value.

COALESCE, returns the first not null expression in the given input parameters.

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