CODEWITHSUNDEEP
mysqlgroup-byduplicateshaving
Andrés Zorrilla
Andrés Zorrilla

Reputation: 111

How to remove " no duplicate" records from a row, in my-sql

For example, If I have

+------------+-------------+
| something_1| something_2 |
+------------+-------------+
| 1          | a           |
| 2          | b           |
| 3          | a           |
| 4          | c           |
| 5          | b           |
| 6          | a           |
| 6          | d           |
| 6          | e           |
+------------+-------------+

I want this, deleting the no-duplicates data:

+-------------+
| something_2 |
+-------------+
| a           |
| b           |    
+-------------+

Thanks, I want it in mysql, please

Upvotes: 0

Views: 45

Answers (2)

sashkello
sashkello

Reputation: 17871

This will give you only the duplicate fields:

SELECT something_2 FROM mytable
GROUP BY something_2
HAVING COUNT(*) > 1

Upvotes: 2

Walter Macambira
Walter Macambira

Reputation: 2605

Let's suppose you have a primary key for your table, do the following:

DELETE FROM my_table WHERE prim_key IN (SELECT prim_key FROM my_table
GROUP BY something_2
HAVING COUNT(*) > 1)

Upvotes: 1

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