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MySQL Query  RSS feed

Richard Green
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Posts: 536
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i have two tables




id text
1something yy1 yy3 blah blah
2 yeah right yy3

I want a sql script to basically go through the names in table1, and see if they are present in table2 and if so, update the "found" field to "Yes"

So, I wrote this

UPDATE table1
SET found = 'Yes'
WHERE exists
( SELECT 1 from table2
where text like concat(concat('%',,'%'))

It worked perfectly in a dev environment (where I had 100 records in table1 and 2), but in prod we have about 2 million records and MySQL just hangs when I run this query.

Any ideas on how to fix this?

Oh btw and table2.text are text fields - I indexed these two fields but that didnt make much difference.
It is sorta covered in the JavaRanch Style Guide.
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