Comments on: SQL Authority News – Download SQL Server Data Type Conversion Chart

By: dastagiri

dastagiri — Sun, 24 Feb 2013 17:06:22 +0000

Thanks sir i am always following ur blog.if we have CONVERT why we r using CAST is der any difference ?

By: Hakan Winther (@h_winther)

Hakan Winther (@h_winther) — Sun, 24 Feb 2013 11:58:16 +0000

A side effect of data type conversion (implicit or explicit) is that it can have negative impact on performance. Assume you get an implicit conversion of the modifieddate in the example above, that will cause an index scan instead of an index seek (if there is an index on modifieddate column).

If you have different datatypes in joins between two tables, you’ll suffer a lot if the implicit conversion will occur on the largest table.

Personally I would prefer if you could turn of implicit conversion (at server, database, connection or statement level) to avoid any unwanted conversions. If you need conversion, you should always have to specify it and it would force you to think of the side effect.

By: Srinivasa Reddy

Srinivasa Reddy — Wed, 19 Dec 2012 07:26:59 +0000

It is really helpfull. Thanks Pinal.

By: kk

kk — Thu, 13 Dec 2012 01:32:40 +0000

Thanks for sharing!!

By: VINAY

VINAY — Mon, 10 Dec 2012 12:59:50 +0000

This chart really useful…….Thank u Pinal

By: @SQLSanjeev

@SQLSanjeev — Sun, 09 Dec 2012 02:36:41 +0000

Great example.