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AskSQLTeam
Ask SQLTeam Question
0 Posts |
 Posted - 2005-06-30 : 07:57:26
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| Abby writes "Hello,I'm a bit new to t-sql in Sql Server. I am writing a vb.net application and am stumped on a how to. This is what I would like to do: have a drop down box with "All" and specific items. I could have 2 seperate queries to handle this, but I'm wondering if I could have one statement to handle both. For a specific item, the sql is pretty simple:Select * where uid = @uidWhere uid is an integer. Since my data key is an integer, I don't know of a wildcard to select all integers or how else I could do this with one sql statement. Any suggestions?Thanks,Abby" |
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dsdeming
479 Posts |
Posted - 2005-06-30 : 08:01:00
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| Select * where uid = @uid or @GetAll = 1If you set @GetAll = 1 you'll get everything. If it = 0, you'll only get rows where uid = @uid.Dennis |
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robvolk
Most Valuable Yak
15732 Posts |
Posted - 2005-06-30 : 08:06:49
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| And if you switch the WHERE clause around:Select * where @GetAll = 1 OR uid = @uidSQL Server will perform a short-circuit evaulation and process the query more quickly (this means that if the first condition is true, it won't even evaluate the second condition, since the entire clause is already true.) |
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spirit1
Cybernetic Yak Master
11752 Posts |
Posted - 2005-06-30 : 08:45:02
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so sql server does process the where conditions in the order they were written??i thought it doesn't...Go with the flow & have fun! Else fight the flow  |
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robvolk
Most Valuable Yak
15732 Posts |
Posted - 2005-06-30 : 19:34:51
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| There are special cases where the optimizer will recognize a short-circuit situation and will not generate a plan for conditions that do not have to be evaluated. |
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Select all or select single integer