SQL DELETE DUPLICATE ROWS
SQL DELETE DUPLICATE ROWS
When dealing with large datasets, it’s common to encounter duplicate records in a table. Duplicate data can cause inaccurate record fetching results if it is not managed appropriately. To ensure accuracy, we must retrieve unique records instead of duplicates.
To solve this issue, SQL provides the DISTINCT keyword, which is used with the SELECT statement to eliminate duplicate records and fetch only unique ones.
Complete Python Course with Advance topics:-Click Here
SQL Tutorial :-Click Here
Using DISTINCT to Remove Duplicates
The DISTINCT keyword helps retrieve unique values from a specific column or a combination of columns. Below is the syntax:
SELECT DISTINCT column1, column2, ....columnN
FROM table_name
WHERE [conditions];
Example
Let’s consider a EMPLOYEE table with duplicate salary records.
| EMP_ID | NAME | SALARY | CITY |
|---|---|---|---|
| 101 | RAHUL VERMA | 50000 | MUMBAI |
| 102 | NEHA SINGH | 48000 | DELHI |
| 103 | ARJUN SHARMA | 50000 | BANGALORE |
| 104 | SAKSHI JAIN | 52000 | KOLKATA |
| 105 | ROHAN MEHTA | 48000 | PUNE |
| 106 | KRITI AGGARWAL | 51000 | CHENNAI |
Checking for Duplicate Salary Records
Before applying DISTINCT, let’s retrieve all salary records to check for duplicates:
SELECT SALARY FROM EMPLOYEE
ORDER BY SALARY;
Output:
| SALARY |
|---|
| 48000 |
| 48000 |
| 50000 |
| 50000 |
| 51000 |
| 52000 |
Using DISTINCT to Remove Duplicates
Now, we apply the DISTINCT keyword to fetch unique salary records:
SELECT DISTINCT SALARY FROM EMPLOYEE
ORDER BY SALARY;
Output:
| SALARY |
|---|
| 48000 |
| 50000 |
| 51000 |
| 52000 |
Duplicate salary values have been removed, as can be seen above.
Download New Real Time Projects :-Click here
Complete Advance AI topics:-Â CLICK HERE
Conclusion
In order to preserve data integrity, SQL must handle duplicate records. The DISTINCT keyword is a simple yet powerful solution to fetch unique records from a table, ensuring accurate and meaningful data retrieval.
For more SQL tutorials and updates, stay tuned to UpdateGadh!
sql delete duplicate rows keep one
delete duplicate rows in sql w3schools
to remove duplicate rows in sql select statement
sql delete duplicate rows with same id
sql delete duplicate rows but keep one without primary key
sql delete duplicate rows based on one column
delete duplicate rows in oracle
delete duplicate records in sql server using row_number
sql delete duplicate rows but keep one
cte sql
sql delete duplicate rows oracle
Post Comment