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Retrieving a SQL expression from a data field?

Posted December 16th, 2008 by Ted Ericson

I need some help with how SQL works. Trying to get an auto-salutation to be generated from data entered in the Gen_Tables.

My thinking was that we could put a SQL expression into the description column in Gen_Tables and then use that as a string in a query, but it does not recognize it as SQL, only as a string.

E.G. the value in the field is: Name.FIRST_NAME+' '+Name.LAST_NAME

Store that value in a variable @value

I was hoping I could use that in a query like this: SELECT @value from Name where ID=’10000’

However that select statement just returns the string “Name.FIRST_NAME+' '+Name.LAST_NAME”

Know any way to tell SQL to recognize that as an expression, not a string?

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You'll need to construct the

On December 16th, 2008 Eric Means says:

You'll need to construct the whole query as dynamic sql and pass it to sp_executesql:

declare @sql nvarchar(4000)
set @sql = 'SELECT ' + @value + ' FROM [Name] WHERE [ID] = ''10000'''
EXEC sp_executesql @sql

Note that you want to be really, really careful about what you pass to this and how; see http://www.sommarskog.se/dynamic_sql.html for a more complete discussion.

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Terrific! I see how that

On December 16th, 2008 Ted Ericson says:

Terrific! I see how that works. Thanks.
Ted Ericson. ASI/Product Management

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