Question

There’s an index table. (Links tags with ids).

REPLACE INTO com_index (word, ids) VALUES ('word1', concat(ids, ' 2')), ('word2', concat(ids, ' 2'))

word is a primary key.

I try to look through rows, add ‘ 2’ to ids in those of them, which exist; and create a new row with ‘ 2’ if it doesn’t.

So, I need to look if there’s any row with such word column (word1 or word2 …) and concat ‘ 2’ to thier ids. And if there is no such rows (with such word column) – create it with ids = ‘ 2’.

And it’s MySQL! (there’s no sub_selects)

Answer 1

A very simple solution that is possible because word is the primary key*:

INSERT INTO `com_index` (word, ids)
VALUES ('word1', '2'), ('word2', '2')
ON DUPLICATE KEY UPDATE ids=concat(ids, ' 2')

Make sure to check the MySQL Manual for the INSERT ... ON syntax

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*actually, it is also possible with other kinds of indexes, as long as they’re unique (which is given with a primary key