

Grasshopper
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Last Login: Friday, October 16, 2015 12:44 PM
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I have a select statement as below, which causes a table access for each union all..
My goal is to cut down the number of table access without using union all..
Select A, B, C, '100' as CntType, count(*) as Cnt from SameTable where A between 1 and 100 and B between 1 and 100 and C between 1 and 100 group by A,B,C Union all Select A, B, C, '200' as CntType, count(*) as Cnt from SameTable where A between 101 and 200 and B between 101 and 200 and C between 101 and 200 group by A,B,C Union all Select A, B, C, '300' as CntType, count(*) as Cnt from SameTable where A between 201 and 300 and B between 201 and 300 and C between 201 and 300 group by A,B,C Union all Select A, B, C, 'Over 300' as CntType, count(*) as Cnt from SameTable where A > 300 and B > 300 and C > 300 group by A,B,C
The above Union all will access the SameTable four times, I'd like to have SQL statements to access the SameTable once..
Please HELP!
Happy Friday...




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This may be way off base but could you add a column to your query and use CASE to populate it based on your A, B & C values? Then you could include that in your GROUP BY.




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Select A, B, C, sum(case when A between 1 and 100 and B between 1 and 100 and C between 1 and 100 then 1 else 0 end) AS '100', sum(case when A between 101 and 200 and B between 101 and 200 and C between 101 and 200 then 1 else 0 end) AS '200', sum(case when A between 201 and 300 and B between 201 and 300 and C between 201 and 300 then 1 else 0 end) AS '300', sum(case when A > 300 and B > 300 and C > 300 then 1 else 0 end) AS 'Over 300' from SameTable where (A between 1 and 100 and B between 1 and 100 and C between 1 and 100) or (A between 101 and 200 and B between 101 and 200 and C between 101 and 200) or (A between 201 and 300 and B between 201 and 300 and C between 201 and 300) or (A > 300 and B > 300 and C > 300) group by A,B,C
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Grasshopper
Group: General Forum Members
Last Login: Friday, October 16, 2015 12:44 PM
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That's great... Let me test it out...



