SQL: Finding Duplicate Reocrds

SELECT Col_1,

 COUNT(Col_1) AS NumOccurrences

FROM Table_Name

GROUP BY Col_1

HAVING ( COUNT(Col_1) > 1 );

SELECT COUNT(*) FROM Table_1;

vs.

SELECT DISTINCT(COUNT(*)) FROM Table_1;

If the different between these two counts are different, then you have an idea how many records are duplicate. Unfortunately, I have not found an easy way to populate duplicates side by side. Please comment if anyone has a better way.

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