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POSQL procedure find 4 matching fields from 5
 

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  1. POSQL procedure find 4 matching fields from 5
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    <p>I am trying to write an sql procedure to identify rows that match on 4 out of 5 columns. Here's an example table:</p> <pre><code>CREATE TABLE [dbo].[Match]( [ID] [int] NULL, [col1] [nchar](10) NULL, [col2] [nchar](10) NULL, [col3] [nchar](10) NULL, [col4] [nchar](10) NULL, [col5] [nchar](10) NULL, [match] [nchar](10) NULL ) ON [PRIMARY] INSERT INTO dbo.Match VALUES ('1','A','A','A','A','A', null) INSERT INTO dbo.Match VALUES ('2','A','A','A','A','B', null) INSERT INTO dbo.Match VALUES ('3','A','A','A','B','A', null) INSERT INTO dbo.Match VALUES ('4','A','A','B','B','A', null) INSERT INTO dbo.Match VALUES ('5','A','B','A','B','A', null) </code></pre> <p>so the procedure should identify that rows 1,2 and 3 have 4 identical field values and row 3 has 4 4 identical field values to row 4 and 5.</p> <p>I tried joining the table to itself and then joining on 4 fields, then doing this for every combination but it doesn't quite do what I want. Any advice would be greatly appreciated.</p> <p>Thanks for replying, I should have been a bit clearer.</p> <p>I need to know that rows 1,2,3 have four field values in common (The A's and B's) and that rows 3,4,5 have four field values in common, then either update a field in that table to record this (so for example write 'group1' to a field for rows 1,2,3 and the same for rows 3,4,5 but when a row is in two groups it might be best to write to another table and add a row to record the matches)</p> <p>I have full control of the schema so can do what I need to.</p> <p>So I don't need to know the number of matches for each row, but record the groups if you like in which all members of the group have four fields in common.</p> <p>thanks again CM</p>
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    1. UScode mechanic
    1. UScode mechanic
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    1. CORow 1 have 5 identical values; rows 4 and 5 have 3 identical values. Or should we also consider `match` column?
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      1. POSQL procedure find 4 matching fields from 5
      1. USRubens Farias
    2. COYou want to match row 3 to each of the other rows and count the matched items, correct? Or do you want to match row 3 to rows 1 and 2 simultaneously and, independently, to rows 4 and 5 simultaneously?
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      1. USAndriy M
 

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