Finding duplicate values in MySQL

gistfile1.sql

SELECT nickname, COUNT(*) c FROM nickname_source GROUP BY nickname HAVING c > 1;

SELECT slugname, COUNT(*) c FROM slug GROUP BY slugname HAVING c > 1;

# duplicate campaigns
SELECT
	entity_campaign_pk,
	campaign_name,
	offers_campaigned,
	options,
	COUNT(*) c
FROM
	entity_campaign
WHERE
	enabled = 1
GROUP BY
	options
HAVING
	c > 1;
    
SELECT
    id, 
    user.email, 
    phone
FROM user
   INNER JOIN (SELECT email
               FROM   user
               WHERE  signedupat_fk=678
               GROUP  BY email
               HAVING COUNT(id) > 1) dup
           ON user.email = dup.email
WHERE signedupat_fk=678;


SELECT
    id, 
    user.phone, 
    email
FROM user
   INNER JOIN (SELECT phone
               FROM   user
               WHERE  signedupat_fk=678
               GROUP  BY phone
               HAVING COUNT(id) > 1) dup
           ON user.phone = dup.phone
WHERE signedupat_fk=678;

-- Duplicates in All users by phone
SELECT
    id, 
    enabled,
    user.phone, 
    user.country_phone_fk,
    email,
    user.utc_created,
    user.signedupat_fk,
    user.platform_solution_fk
FROM user
   INNER JOIN (SELECT phone
               FROM   user
               WHERE  phone > 0
               GROUP  BY phone
               HAVING COUNT(id) > 1) dup
           ON user.phone = dup.phone
WHERE user.phone > 0;

# shows each row that is a duplicate.
SELECT firstname, 
   lastname, 
   list.address 
FROM list
   INNER JOIN (SELECT address
               FROM   list
               GROUP  BY address
               HAVING COUNT(id) > 1) dup
           ON list.address = dup.address;
	  
-- Find duplicated sales for account
SELECT
	ps.pos_sale_pk,
	ps.account_id,
	ps.sale_id,
	ps.sale_customer_id,
	ps.user_fk,
	ps.utc_created
FROM pos_sale ps
   INNER JOIN (SELECT account_id, sale_id
               FROM   pos_sale
               GROUP  BY account_id, sale_id
               HAVING COUNT(pos_sale_pk) > 1) duplicated
           ON ps.account_id = duplicated.account_id AND ps.sale_id = duplicated.sale_id;
	  

-- Duplicated transactions
SELECT
	t.transaction_pk,
	t.user_fk,
	t.transaction_sub_type_fk
FROM
	`transaction` t
INNER JOIN (
	SELECT
		transaction_pk,
		user_fk
	FROM
		`transaction`
	WHERE
		entity_fk = 12345678
	GROUP BY
		user_fk
	HAVING
		COUNT(transaction_pk) > 1
) duplicated ON t.user_fk = duplicated.user_fk
WHERE
	t.entity_fk = 12345678;