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Compare one row with another in a Table !


Compare one row with another in a Table !

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drew.allen
drew.allen
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dwain.c (1/7/2013)

Any solution posed with a CTE can always be done without the CTE by making the CTE into a derived table as Lynn has shown.


That's not entirely true. It's only true if the CTE is not recursive. Recursive CTEs cannot simply be rewritten as derived tables.

Even where they can be rewritten as derived tables, I find the CTE syntax easier to understand, and would recommend using the CTE in any case.

Drew

J. Drew Allen
Business Intelligence Analyst
Philadelphia, PA
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dwain.c
dwain.c
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drew.allen (1/9/2013)
dwain.c (1/7/2013)

Any solution posed with a CTE can always be done without the CTE by making the CTE into a derived table as Lynn has shown.


That's not entirely true. It's only true if the CTE is not recursive. Recursive CTEs cannot simply be rewritten as derived tables.

Even where they can be rewritten as derived tables, I find the CTE syntax easier to understand, and would recommend using the CTE in any case.

Drew


Drew - 100% correct. Can't understand why I didn't think of that considering the number of rCTEs I've posted to this site.


My mantra: No loops! No CURSORs! No RBAR! Hoo-uh!

My thought question: Have you ever been told that your query runs too fast?

My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.


Need to UNPIVOT? Why not CROSS APPLY VALUES instead?
Since random numbers are too important to be left to chance, let's generate some!
Learn to understand recursive CTEs by example.
Splitting strings based on patterns can be fast!
My temporal SQL musings: Calendar Tables, an Easter SQL, Time Slots and Self-maintaining, Contiguous Effective Dates in Temporal Tables
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