how to duplicate data in sql table code example

Example 1: duplicate records in sql

Multiple field=
SELECT username, email, COUNT(*)
FROM users
GROUP BY username, email
HAVING COUNT(*) > 1

Single field=
SELECT _column, COUNT(*) 
FROM _table
GROUP BY _column
HAVING COUNT(*) > 1

Example 2: sql how to duplicate a table

CREATE TABLE new_table LIKE original_table;
INSERT INTO new_table SELECT * FROM original_table;