====== Trouver les doublons ======

{{ :informatique:langage:sql:sql_table_records.jpg?nolink&75x75|Trouver des doublons en SQL}}

~~NOTOC~~

<panel type="default" title="Code SQL">
<code SQL [enable_line_numbers="true", start_line_numbers_at="1"]>
SELECT   COUNT(*) AS nbr_doublon, champ1, champ2, champ3
FROM     table
GROUP BY champ1, champ2, champ3
HAVING   COUNT(*) > 1
</code>
</panel>

<panel type="default" title="Code SQL">
<code SQL [enable_line_numbers="true", start_line_numbers_at="1"]>
SELECT DISTINCT *
FROM table t1
WHERE EXISTS (
              SELECT *
              FROM table t2
              WHERE t1.ID <> t2.ID
              AND   t1.champ1 = t2.champ1
              AND   t1.champ2 = t2.champ2
              AND   t1.champ3 = t2.champ3 )
</code>
</panel>