Please start any new threads on our new
site at https://forums.sqlteam.com. We've got lots of great SQL Server
experts to answer whatever question you can come up with.
Author |
Topic |
sportsguy
Starting Member
39 Posts |
Posted - 2013-02-04 : 15:34:14
|
The Step by Step book by Mike Hotek shows how to create calculated columns, and that is fine.However, can the calculation include an IIF statement?I only want to calculate aver prices where there is a positive,greater than zero volume.thanks in advance.sportsguy. . . .MS Access 20 years, SQL hack |
|
TG
Master Smack Fu Yak Hacker
6065 Posts |
Posted - 2013-02-04 : 15:45:08
|
Yes, IIF or CASE expressions can be used for either computed columns or in a SELECT list.ie:assuming a column called [volume] and assuming you want to return NULL if it is not greater than 0:case when [volume] > 0 then [volume] else null endEDIT:orIIF([volume] > 0, [volume], null)Be One with the OptimizerTG |
|
|
visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2013-02-04 : 22:51:32
|
are you asking about MS Access query of Transact SQL query?If former you can use as TG suggestedIf in T-SQL, IIF is available only from SQL 2012 onwards so if you're on an earlier version you should be using CASE...WHEN instead------------------------------------------------------------------------------------------------------SQL Server MVPhttp://visakhm.blogspot.com/ |
|
|
sportsguy
Starting Member
39 Posts |
Posted - 2013-02-05 : 12:12:03
|
TG,Got it, thanks, understand perfectly. Next quick question. . . can i change an existing column from numeric to calculated?or do I have to drop the column and add it back? somehow i suspect the latter, but just wanted to ask - definately a noob question! sportsguyMS Access 20 years, SQL hack |
|
|
visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2013-02-05 : 12:20:20
|
from Books onlineALTER COLUMNSpecifies that the named column is to be changed or altered.The modified column cannot be any one of the following:A column with a timestamp data type.The ROWGUIDCOL for the table.A computed column or used in a computed column.------------------------------------------------------------------------------------------------------SQL Server MVPhttp://visakhm.blogspot.com/ |
|
|
|
|
|
|
|