Do you know how to count duplicate values in sql ?

for count douplicate value in sql can use Group By and Having...

SELECT FIELD, COUNT(FIELD) FROM TABLE GROUP BY FIELD HAVING COUNT(FIELD)>1;

select column_name,count(column_name) from Table_namehaving count(column_name) > 1group by column_name

If you have a column with duplicated values, and you want to know what are those duplicated values are and how many duplicates are there for each of those values, you can use the "GROUP BY ... HAVING" clause.

To count all the duplicate records in a column of the table use this code:

SELECT Column_name, COUNT(*) Count_Duplicate FROM Table_name GROUP BY Column_name HAVING COUNT(*) > 1 ORDER BY COUNT(*) DESC

To count all the duplicate records in two columns of the table:

SELECT Column1, Column2, COUNT(*) Count_Duplicate FROM Table_name GROUP BY Column1, Column2 HAVING COUNT(*) > 1 ORDER BY COUNT(*) DESC

To count all the duplicate records in all columns of the table:

SELECT , COUNT(*) Count_Duplicate FROM Table_name GROUP BY HAVING COUNT(*) > 1 ORDER BY COUNT(*) DESC

SELECT name, email, COUNT(value) 

FROM users 

GROUP BY name, email

HAVING COUNT(value) > 1

Using group by  . exemple :

Select product_code, product_name , count(*) from product 

group by product_code, product_name  

having count(*) > 1

Here we want to know which products found in the result more than one time .

SELECT COLUMN_NAME,COUNT(COLUMN_NAME) GROUP BY COLUMN_NAME HAVING COUNT(*)>1

select *

form tables,

Group by coulmnName,

having count(*)>1;

below query to find duplicate for given columns

SELECT name, email, COUNT(*)FROM users GROUPBY name,email HAVING COUNT(*)>1 

Use count(*)  group by on the column you want to find duplicates and then filter count(*) >1