find rows with same column value sql code example

Example 1: 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

Example 2: select all same column value in sql

SELECT RollId, count(*) AS c FROM `tblstudents` GROUP BY RollId HAVING c > 1 ORDER BY c DESC