sql find same row code example

Example 1: sql get rows with duplicate values

/* Gets reps */
SELECT fieldA, COUNT(*)
FROM tableA
GROUP BY fieldA
HAVING COUNT(*) > 1

/* Use reps to filter results */
SELECT a.*
FROM tableA a
JOIN (
	SELECT fieldA, COUNT(*) as 'count'
	FROM tableA
	GROUP BY fieldA
	HAVING COUNT(*) > 1
) b
ON a.fieldA = b.fieldA

Example 2: sql check same row

//  select duplicate -------------
-- users (name, email) --
// -------------------------------

SELECT
    id, school_id, COUNT(*)
FROM
    booster_school_languages
GROUP BY
    id, school_id
HAVING 
    COUNT(*) > 3