Using group_concat with update statement in MySql - mysql

Question

I am trying to execute the below update query using GROUP_CONCAT but it is failing.
Can anyone kindly help me in correcting it, moreover the statement must always start with the “update” keyword is the catch here as well.
UPDATE firstEntry f,
objects o,
titlement_values e
SET e.customattribute12 = (
SELECT GROUP_CONCAT(DISTINCT o.minvalue)
WHERE f.ldkey = o.ld_key
AND o.TITLE_VALUEKEY = e.TITLE_VALUEKEY
AND e.TITLE_VALUE = 'ZD%'
AND f.ldkey = 13
AND e.TITLEMENTTYPEKEY = 13
GROUP BY e.title_value)
I tried to execute the below query as well but no luck in it as well:
UPDATE firstEntry f,
objects o,
titlement_values e
SET e.customattribute12 = minval
FROM (SELECT GROUP_CONCAT(DISTINCT o.minvalue) AS minval,
e.title_value
WHERE f.ldkey = o.ld_key
AND o.TITLE_VALUEKEY = e.TITLE_VALUEKEY
AND e.TITLE_VALUE = 'ZD%'
AND f.ldkey = 13
AND e.TITLEMENTTYPEKEY = 13
GROUP BY e.title_value)
Here is the table result of using select statement on joining the 3 tables mentioned in the query
group_concat
e.titlement_value
A1,A2,A3
Zd_A
A1,B2
Zd_B
Now i need to take the value of this group_concat and update it in the column e.customattribute12 as shown
e.titlement_value
e.customattribute12
zd_A
A1,A2,A3
zd_B
A1,B2

Answer 1

You need to rewrite your update as MySQL doesn't support FROM clauses in UPDATE statements: a correlated subquery will do the trick, as it returns only one scalar value.
Also JOIN operations are around for 30 years and are established standard, you should switch also to it.
with the problem you mentioned in the comment.
mjava.sql.BatchUpdateException: You can't specify target table 'e' for update in FROM claus
it os MySQL error 1063
MySQL doesn't like when the updated table is in somewhere used again, we can avoid that with a trick seen below, as we force MySql to produce a new temporary table
UPDATE titlement_values e
SET
e.customattribute12 = (SELECT
GROUP_CONCAT(DISTINCT o.minvalue)
FROM
firstEntry f
INNER JOIN
objects o ON f.ldkey = o.ld_key
INNER JOIN
(SELECT * FROM titlement_values) e1 ON o.TITLE_VALUEKEY = e1.TITLE_VALUEKEY
WHERE
e1.TITLE_VALUE LIKE 'ZD%' AND f.ldkey = 13
AND e1.TITLEMENTTYPEKEY = 13
AND e1.title_value = e.title_value)

Answer 2

Once you are able to make sure that the subquery works correctly, try applying the join between your table to be updated and your crafted subquery, on matching "title_value" values.
UPDATE titlement_values
INNER JOIN (SELECT GROUP_CONCAT(DISTINCT o.minvalue) AS minval,
e.title_value
FROM firstEntry f
INNER JOIN objects o ON f.ldkey = o.ld_key
INNER JOIN titlement_values e ON o.TITLE_VALUEKEY = e.TITLE_VALUEKEY
WHERE e.TITLE_VALUE LIKE 'ZD%'
AND f.ldkey = 13
AND e.TITLEMENTTYPEKEY = 13 ) cte
ON titlement_values.title_value = cte.title_value
SET customattribute12 = cte.minval