Check if value exists before doing update [closed]

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Check if value exists before doing update [closed]

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#1 by (4 votes)

-8

I need to do a query to update a column, but only update the column if the data to be updated does not currently exist in that column.

postgresql

asked by anonymous 19.08.2015 / 13:36

1 answer

Counter of days elapsed since a certain date, using the form [closed] Object orientation is the part of C # used for games? [closed]

score 4 · Answer 1

The ideal is to leave the field UNIQUE , but if for some reason you need to do, you can use a query similar to this:

UPDATE 
    suatabela 
SET 
    seucampo = 'seuvalor' 
WHERE 
    seucampo NOT IN (SELECT 
                        COUNT(seucampo) 
                    FROM 
                        suatabela 
                    WHERE 
                        seucampo = 'seuvalor')