SQL UPDATE all values in a field with appended string CONCAT not working

Question

Here is what I want to do:

current table:

+----+-------------+  
| id | data        |  
+----+-------------+  
|  1 | max         |  
|  2 | linda       |  
|  3 | sam         |  
|  4 | henry       |  
+----+-------------+

Mystery Query ( something like "UPDATE table SET data = CONCAT(data, 'a')" )

resulting table:

+----+-------------+  
| id | data        |  
+----+-------------+  
|  1 | maxa        |  
|  2 | lindaa      |  
|  3 | sama        |  
|  4 | henrya      |  
+----+-------------+

thats it! I just need to do it in a single query, but can't seem to find a way. I am using mySQL on bluehost (I think its version 4.1)

Thanks everyone.

here is my 'real life' return: [SQL] UPDATE questions_national SET cat_id = CONCAT(cat_id,'a') Affected rows: 0 Time: 0.069ms — Fresheyeball, Nov 08 '10 at 22:00
Is `cat_id` a character field (varchar, text, etc) or numeric? — Phil, Nov 08 '10 at 23:02
was not working for me (SQL 2012)so I tried "update t set data=data+'a'" works fine.. — Silver, Nov 29 '16 at 07:46

score 324 · Accepted Answer · answered Nov 08 '10 at 21:46

324

That's pretty much all you need:

mysql> select * from t;
+------+-------+
| id   | data  |
+------+-------+
|    1 | max   |
|    2 | linda |
|    3 | sam   |
|    4 | henry |
+------+-------+
4 rows in set (0.02 sec)

mysql> update t set data=concat(data, 'a');
Query OK, 4 rows affected (0.01 sec)
Rows matched: 4  Changed: 4  Warnings: 0

mysql> select * from t;
+------+--------+
| id   | data   |
+------+--------+
|    1 | maxa   |
|    2 | lindaa |
|    3 | sama   |
|    4 | henrya |
+------+--------+
4 rows in set (0.00 sec)

Not sure why you'd be having trouble, though I am testing this on 5.1.41

answered Nov 08 '10 at 21:46

Marc B

356,200
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1

The `concat` function in 4.1 looks the same - http://dev.mysql.com/doc/refman/4.1/en/string-functions.html#function_concat – Phil Nov 08 '10 at 21:50
14

Solved it. Turns out the column had a limited set of characters it would accept, changed it, and now the query works fine. – Fresheyeball Nov 09 '10 at 03:19
I have somewhat the same senario, except i want to replace all the double quotes with single quotes. Any suggestions how can i do that? – Shaonline Feb 10 '17 at 14:19
2

This was a good answer, but a little confusing, since on my server 'data' was a keyword. Maybe a less ambiguous example would be: `UPDATE table SET column_name=concat(column_name, 'string');` – Kiky Rodriguez Dec 11 '18 at 19:09

andrejc · Answer 2 · 2013-11-14T11:38:10.297

46

CONCAT with a null value returns null, so the easiest solution is:

UPDATE myTable SET spares = IFNULL (CONCAT( spares , "string" ), "string")

edited Nov 14 '13 at 11:38

answered Nov 14 '13 at 11:31

andrejc

480
4
6

Perfect solution. – REMITH Feb 28 '21 at 07:40

score 17 · Answer 3 · answered Nov 04 '15 at 10:02

17

convert the NULL values with empty string by wrapping it in COALESCE

"UPDATE table SET data = CONCAT(COALESCE(`data`,''), 'a')"

OR

Use CONCAT_WS instead:

"UPDATE table SET data = CONCAT_WS(',',data, 'a')"

answered Nov 04 '15 at 10:02

Rohan Khude

4,455
5
49
47

score 15 · Answer 4 · edited Sep 21 '12 at 16:49

15

UPDATE 
    myTable
SET 
    col = CONCAT( col , "string" )

Could not work it out. The request syntax was correct, but "0 line affected" when executed.

The solution was :

UPDATE 
    myTable 
SET 
    col = CONCAT( myTable.col , "string" )

That one worked.

edited Sep 21 '12 at 16:49

andrewsi

10,807
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answered Sep 21 '12 at 10:55

Jeremy Thille

26,047
12
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score 12 · Answer 5 · edited Oct 29 '12 at 08:41

12

UPDATE mytable SET spares = CONCAT(spares, ',', '818') WHERE id = 1

not working for me.

spares is NULL by default but its varchar

edited Oct 29 '12 at 08:41

coolguy

7,866
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answered Sep 23 '12 at 10:12

DS_web_developer

3,622
13
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83

5

it seems, that if the value is NULL by default it doesnt work. it has to be an empty string – DS_web_developer Sep 23 '12 at 10:26
`UPDATE mytable SET spares = CONCAT(COALESCE(spares, ''), ',', '818') WHERE id = 1` This will work. It uses a blank string `''` when it runs into null values. – pbarney Jun 10 '21 at 19:26

score 8 · Answer 6 · answered Nov 09 '10 at 03:20

8

Solved it. Turns out the column had a limited set of characters it would accept, changed it, and now the query works fine.

answered Nov 09 '10 at 03:20

Fresheyeball

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score 3 · Answer 7 · answered May 24 '13 at 18:19

3

You can do this:

Update myTable
SET spares = (SELECT CASE WHEN spares IS NULL THEN '' ELSE spares END AS spares WHERE id = 1) + 'some text'
WHERE id = 1

field = field + value does not work when field is null.

answered May 24 '13 at 18:19

Eric

695
9
25

Can you really use + with strings in mysql ? – Sudhir N Dec 01 '15 at 16:15

SQL UPDATE all values in a field with appended string CONCAT not working

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