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intergalacticplanetary
Starting Member
12 Posts |
 Posted - 2007-02-06 : 16:11:43
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| hi, i'm having difficulty figuring out how to implement a set difference between two queries. the only set operator i've been able to come across is union. thanks in advance!d |
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sshelper
Posting Yak Master
216 Posts |
Posted - 2007-02-06 : 16:13:49
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| To be able to do a set difference, you can either use the NOT EXISTS, NOT IN, or LEFT OUTER JOIN. For more information about these options, you can refer to question #3 in the following link:http://www.sql-server-helper.com/faq/select-p01.aspxSQL Server Helperhttp://www.sql-server-helper.com |
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intergalacticplanetary
Starting Member
12 Posts |
Posted - 2007-02-06 : 16:28:39
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quote:
Originally posted by sshelper
To be able to do a set difference, you can either use the NOT EXISTS, NOT IN, or LEFT OUTER JOIN.
hi, i'm familiar with those operators but am not sure how to use them with multiple columns. for example, i have two tables with the same 2 columns and i want to return only those rows in table 1 that are not also in table 2. i've been doing this:SELECT column_1, column_2FROM table_1WHERE column_1 NOT IN (SELECT column_1 FROM table_2)AND column_2 NOT IN (SELECT column_2 FROM table_2);...however, as expected, this doesn't return the proper results. it performs independent checks on the column values where i'm looking to remove rows that have the same unique column_1, column_2 combination. |
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intergalacticplanetary
Starting Member
12 Posts |
Posted - 2007-02-06 : 16:35:51
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| got it figured out...thanks anyway! |
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set difference?