Select without duplicate values in one column

Question

My construction:

INSERT INTO ... ( SELECT ... FROM .. JOIN ... ON ... WHERE ... ORDER BY ... )

Short description: I'm using Select to insert data from 2 tables (using JOIN) to another table. The result of Select is something like (after order by):

col_a  |  col_b  |  col_c |        col_d

1111       44         xxx            yyy
1111       66         xxx            yyy
2222       12         aaa            bbb
3333       55         ccc            ddd
3333       68         xxx            yyy

If the row is duplicated (col_c) i want to insert to my table first matched row.

Example of result should be like this:

col_a  |  col_b  |  col_c |        col_d

1111       44         xxx            yyy
2222       12         aaa            bbb
3333       55         ccc            ddd

Please add the query like you already have.... on which column do you want to order by? And you only want to check on duplicate in col_c? — arnoudhgz, Feb 11 '15 at 19:30
Use insert .. on duplicate like explained [here](http://stackoverflow.com/questions/13041023/insert-on-duplicate-key-update-nothing-using-mysql/13041065#13041065) — A.D., Feb 11 '15 at 19:32

score 2 · Answer 1 · answered Feb 11 '15 at 19:31

2

Use the GROUP BY function

(SELECT ... FROM .. JOIN ... ON ... WHERE ... ORDER BY ... GROUP BY [col_c])

answered Feb 11 '15 at 19:31

Ramie

1,171
2
16
35

GROUP BY is executing before ORDER BY .. I want to first ORDER my result and then eliminate duplicates – Chris Feb 11 '15 at 19:37

score 0 · Answer 2 · answered Feb 11 '15 at 20:05

0

I think I found a solution. I create unique key for the col in table. After that INSERT IGNORE is everyhing what I need :)

answered Feb 11 '15 at 20:05

Chris

652
1
7
22

Select without duplicate values in one column

2 Answers2