MySQL Find Duplicate Values in Table

1. How do I find duplicate values in mysql?
2. How do you find duplicates in a table?
3. How do I find duplicates in SQL table?
4. Can a table contain duplicate records?
5. What is the formula for finding duplicates in Excel?
6. How can I add duplicate rows in mysql?
7. How do I print duplicate rows in a table?
8. How do you eliminate duplicate rows in SQL query without distinct?
9. How find and delete duplicate rows in SQL?
10. How do you find the second highest salary in SQL?
11. How can I get maximum salary in each department?
12. How do I eliminate duplicates in SQL?

How do I find duplicate values in mysql?

Find duplicate values in one column

1. First, use the GROUP BY clause to group all rows by the target column, which is the column that you want to check duplicate.
2. Then, use the COUNT() function in the HAVING clause to check if any group have more than 1 element. These groups are duplicate.

How do you find duplicates in a table?

Using GROUP BY clause to find duplicates in a table

1. First, the GROUP BY clause groups the rows into groups by values in both a and b columns.
2. Second, the COUNT() function returns the number of occurrences of each group (a,b).

How do I find duplicates in SQL table?

How to Find Duplicate Values in SQL

1. Using the GROUP BY clause to group all rows by the target column(s) – i.e. the column(s) you want to check for duplicate values on.
2. Using the COUNT function in the HAVING clause to check if any of the groups have more than 1 entry; those would be the duplicate values.

Can a table contain duplicate records?

According to database design best practices, a SQL Server table should not contain duplicate rows. During the database design process primary keys should be created to eliminate duplicate rows. ... For example, when a staging table is used and data is loaded from different sources where duplicate rows are possible.

What is the formula for finding duplicates in Excel?

How to identify duplicates in Excel

1. Input the above formula in B2, then select B2 and drag the fill handle to copy the formula down to other cells: ...
2. =IF(COUNTIF($A$2:$A$8, $A2)>1, "Duplicate", "Unique") ...
3. The formula will return "Duplicates" for duplicate records, and a blank cell for unique records:

How can I add duplicate rows in mysql?

MySQL INSERT ON DUPLICATE KEY UPDATE

1. mysql> INSERT INTO tab1 (col1, col2, col3) VALUES (10,20,30) ON DUPLICATE KEY UPDATE col3=col3+1;
2. mysql> UPDATE tab1 SET col3=col3+1 WHERE col1=1;

How do I print duplicate rows in a table?

This is a temporary table, on which we can run the below code to get duplicate NAME. select NAME from ( select NAME, count(NAME) as num from Person group by NAME ) as statistic where num > 1; The Best approach is to use GROUP BY and HAVING condition. It is more effective and faster then previous.

How do you eliminate duplicate rows in SQL query without distinct?

Below are alternate solutions :

1. Remove Duplicates Using Row_Number. WITH CTE (Col1, Col2, Col3, DuplicateCount) AS ( SELECT Col1, Col2, Col3, ROW_NUMBER() OVER(PARTITION BY Col1, Col2, Col3 ORDER BY Col1) AS DuplicateCount FROM MyTable ) SELECT * from CTE Where DuplicateCount = 1.
2. Remove Duplicates using group By.

How find and delete duplicate rows in SQL?

To delete the duplicate rows from the table in SQL Server, you follow these steps:

1. Find duplicate rows using GROUP BY clause or ROW_NUMBER() function.
2. Use DELETE statement to remove the duplicate rows.

How do you find the second highest salary in SQL?

IN SQL Server using Common Table Expression or CTE, we can find the second highest salary: WITH T AS ( SELECT * DENSE_RANK() OVER (ORDER BY Salary Desc) AS Rnk FROM Employees ) SELECT Name FROM T WHERE Rnk=2; How to find the third largest salary?

How can I get maximum salary in each department?

if use salary in (select max(salary...))

The below listed query will list highest salary in each department. select deptname, max(salary) from department, employee where department.

How do I eliminate duplicates in SQL?

The go to solution for removing duplicate rows from your result sets is to include the distinct keyword in your select statement. It tells the query engine to remove duplicates to produce a result set in which every row is unique. The group by clause can also be used to remove duplicates.