Converting date stored as a varchar
You can use CAST to convert your VARCHAR value into DATE format.

Syntax for CAST:

CAST ( expression AS data_type [ ( length ) ] )




Sample execution: You can convert into DATE alone or DATETIME format:

DECLARE @TestDate AS VARCHAR (12) = '22-MAY-2015';
SELECT CAST(@TestDate AS DATE);


Output: 2015-05-22

DECLARE @TestDate1 AS VARCHAR (12) = '22-MAY-2015';
SELECT CAST(@TestDate1 AS DATETIME);


Output: 2015-05-22 00:00:00.000