Friday 29 July 2011

Declared Variable has NULL as Default Value!

When we declare a variable, by default it has NULL as its default value. So, need to be careful when checking the variable's value.

-- similar result for CHAR
DECLARE @varString VARCHAR(20)	
SELECT @varString
-- result is NULL

-- similar result for DECIMAL, FLOAT and DATETIME
DECLARE @varNumber INTEGER
SELECT @varNumber
-- result is NULL

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