Is there any size limit on a MySQL query?

Databases
1

hi guys

i have tables which I query with a “huge” query string, and it’s different
each time it run … And it also grows over time.

So, is there any upper limit how large a query string can be?

Sample:

CREATE OR REPLACE VIEW v_view as
SELECT id FROM table_1 UNION
SELECT id FROM table_2 UNION
…
SELECT id FROM table_n

with n>500000

thank guys

2

Just out of curiousity, how comes you have so many tables?

3

hi guido2004

because I have many blogs (about 20,000 blogs), each blog has about 10 tables

have you know “how large a query string can in mysql?”

thank replay

4

No I don’t know, sorry.
Did you try “unioning” them? What happened?
I have a feeling you might encounter some serious performance problems before you reach the limit of the query string length. But I might be wrong, I’ve never worked in such a situation.

5

ok, no problem

I wanted including the group tables to view, search in the view (search all blogs)

6

you should have 10 tables overall, then, not 10 per blog

20,000 blogs??? whoa!!!

who updates all these blogs (surely not you) – and more importantly, what’s in them?

7

hi r937
I am using Wordpress to manage the blogs( plugin MultiSite), multisite created by the 9 tables each blog, and I use Global Search Multisite plugin to create view search all blog (not 9 tables overall) but a database very large, not create view.

What’s your idea for this?

thank replay

ps: I am very sorry for late reply

8

i’m sorry, i don’t know what to tell you