duplicate query in sql code example

Example 1: select duplicates in sql

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

Example 2: 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 3: sql how to duplicate a table

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

Example 4: FIND DUPLICATES IN COLUMN SQL

declare @YourTable table (id int, name varchar(10), email varchar(50))

INSERT @YourTable VALUES (1,'John','John-email')
INSERT @YourTable VALUES (2,'John','John-email')
INSERT @YourTable VALUES (3,'fred','John-email')
INSERT @YourTable VALUES (4,'fred','fred-email')
INSERT @YourTable VALUES (5,'sam','sam-email')
INSERT @YourTable VALUES (6,'sam','sam-email')

SELECT
    name,email, COUNT(*) AS CountOf
    FROM @YourTable
    GROUP BY name,email
    HAVING COUNT(*)>1

Example 5: duplicate in sql

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