It converts an expression from one data type to another.
CAST and CONVERT have similar functionality.
SQL CAST and CONVERT Syntax
Using CAST:
CAST ( expression AS data_type )
Using CONVERT:
CONVERT ( data_type [ ( length ) ] , expression [ , style ] )
Example of SQL Cast and Convert
SQL Cast and Convert - String
SELECT SUBSTRING('CAST and CONVERT', 1, 3)
Return Value = CAS (it get from index 1 to 3)
SELECT CAST('CAST and CONVERT' AS char(3))
Return Value = CAS (it get 3 char only)
SQL Cast and Convert - Date Time
-Converting date time to character data(vachar)
-The default values (style 0 or 100, 9 or 109, 13 or 113, 20 or 120, and 21 or 121) always return the Without century year(yy).
-Add 100 to a style value to get a four-place year that includes the century year(yyyy).
-Below is example for converting 1 format of date time to different format of date time, so that it can be use in various condition.
Value of current Date Time GETDATE()
SELECT (GETDATE()) = 2007-06-06 23:41:10.153
SELECT CONVERT(varchar,GETDATE(),0)
Return Value = Jun 6 2007 11:07PM
SELECT CONVERT(varchar,GETDATE(),100)
Return Value = Jun 6 2007 11:07PM
SELECT CONVERT(varchar,GETDATE(),1)
Return Value = 06/06/07
SELECT CONVERT(varchar,GETDATE(),101)
Return Value = 06/06/2007
SELECT CONVERT(varchar,GETDATE(),2)
Return Value = 07.06.06
SELECT CONVERT(varchar,GETDATE(),102)
Return Value = 2007.06.06
SELECT CONVERT(varchar,GETDATE(),3)
Return Value = 06/06/07
SELECT CONVERT(varchar,GETDATE(),103)
Return Value = 06/06/2007
SELECT CONVERT(varchar,GETDATE(),4)
Return Value = 06.06.07
SELECT CONVERT(varchar,GETDATE(),104)
Return Value = 06.06.2007
SELECT CONVERT(varchar,GETDATE(),5)
Return Value = 06-06-07
SELECT CONVERT(varchar,GETDATE(),105)
Return Value = 06-06-2007
SELECT CONVERT(varchar,GETDATE(),6)
Return Value = 06 Jun 07
SELECT CONVERT(varchar,GETDATE(),106)
Return Value = 06 Jun 2007
SELECT CONVERT(varchar,GETDATE(),7)
Return Value = Jun 06, 07
SELECT CONVERT(varchar,GETDATE(),107)
Return Value = Jun 06, 2007
SELECT CONVERT(varchar,GETDATE(),8)
Return Value = 23:38:49
SELECT CONVERT(varchar,GETDATE(),108)
Return Value = 23:38:49
SELECT CONVERT(varchar,GETDATE(),9)
Return Value = Jun 6 2007 11:39:17:060PM
SELECT CONVERT(varchar,GETDATE(),109)
Return Value = Jun 6 2007 11:39:17:060PM
SELECT CONVERT(varchar,GETDATE(),10)
Return Value = 06-06-07
SELECT CONVERT(varchar,GETDATE(),110)
Return Value = 06-06-2007
SELECT CONVERT(varchar,GETDATE(),11)
Return Value = 07/06/06
SELECT CONVERT(varchar,GETDATE(),111)
Return Value = 2007/06/06
SELECT CONVERT(varchar,GETDATE(),12)
Return Value = 070606
SELECT CONVERT(varchar,GETDATE(),112)
Return Value = 20070606
SELECT CONVERT(varchar,GETDATE(),13)
Return Value = 06 Jun 2007 23:40:14:577
SELECT CONVERT(varchar,GETDATE(),113)
Return Value = 06 Jun 2007 23:40:14:577
SELECT CONVERT(varchar,GETDATE(),14)
Return Value = 23:40:29:717
SELECT CONVERT(varchar,GETDATE(),114)
Return Value = 23:40:29:717
SELECT CONVERT(varchar,GETDATE(),20)
Return Value = 2007-06-06 23:40:51
SELECT CONVERT(varchar,GETDATE(),120)
Return Value = 2007-06-06 23:40:51
SELECT CONVERT(varchar,GETDATE(),21)
Return Value = 2007-06-06 23:41:10.153
SELECT CONVERT(varchar,GETDATE(),121)
Return Value = 2007-06-06 23:41:10.153
SELECT CONVERT(varchar,GETDATE(),126)
Return Value = 2007-06-06T23:41:10.153
SELECT CONVERT(varchar,GETDATE(),131)
Return Value = 21/05/1428 11:41:10:153PM
