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SQL Conditional Where Clause Not Use Subquery?

Posted on 2014-07-14
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Last Modified: 2014-07-14
I have a typical Stored Procedure using a Where clause and Max(Update_Date) subquery. I need to conditional NOT use the Max(Update_Date) query, completely by-pass it.  I haven't written a query like this before and unsure how to proceed, help...

[Summary]
1. If @myVariableString is empty, then use the Max(Update_Date) query
2. If @myVariableString not empty, then by-pass the Max(Update_Date) query all together.

@myVariableString varchar(4000)

Select   * 
From    Advertising a
Where Case When @myVariableString = '' 
                      Then  Update_Date = (Select Max(Update_Date) 
                                                      From Advertising b 
                                                      Where a.Name = b.Name)
             End 

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Question by:WorknHardr
3 Comments
 
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Expert Comment

by:Randy Poole
ID: 40195105
Not 100% what your looking for, but see if this is it:

Select   *,case when isNull(@myVariableString,'')='' then 
(Select top 1 Update_Date From Advertising b Where a.Name = b.Name order by Update_Date desc) 
else Update_Date end as Update_Datenew
From    Advertising a

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Accepted Solution

by:
Scott Pletcher earned 1800 total points
ID: 40195133
Select   *
From    Advertising a
Where
    (@myVariableString > '' OR a.Update_Date = (Select Max(b.Update_Date)
                                                      From Advertising b
                                                      Where a.Name = b.Name))
0
 

Author Closing Comment

by:WorknHardr
ID: 40195255
Excellent! thx
0

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