Answers for "why duplicates are forming in sql"

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

sql how to duplicate a table

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

duplicate in sql

• SELECT first_name, COUNT (first_name) FROM employees
GROUP BY first_name
HAVING (COUNT(first_name) > 1);