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Iczer

SQLite Update/Join

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I want to update Mark column from main table if  Info column correspond pattern from one of the rows in second table

UPDATE MainTable SET Mark = Mark | 8 WHERE IDColumn IN (SELECT IDColumn FROM MainTable JOIN pTable ON MainTable.Info LIKE pTable.Pattern WHERE Title IS 'qqqqqqq');

but it works very slow...  is there a way to speed up query and still use patterns "%aaa%bbb_ccc%" from another table?

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Speed of such statement slightly depends on which indices you have created. Note that recent SQLite libraries offer support to partial indices but this probably won't make you any good in the case of such multi-LIKE pattern.

Use "explain query plan ..." to see what the engine does with it.


This wonderful site allows debugging and testing regular expressions (many flavors available). An absolute must have in your bookmarks.
Another excellent RegExp tutorial. Don't forget downloading your copy of up-to-date pcretest.exe and pcregrep.exe here
RegExp tutorial: enough to get started
PCRE v8.33 regexp documentation latest available release and currently implemented in AutoIt beta.

SQLitespeed is another feature-rich premier SQLite manager (includes import/export). Well worth a try.
SQLite Expert (freeware Personal Edition or payware Pro version) is a very useful SQLite database manager.
An excellent eBook covering almost every aspect of SQLite3: a must-read for anyone doing serious work.
SQL tutorial (covers "generic" SQL, but most of it applies to SQLite as well)
A work-in-progress SQLite3 tutorial. Don't miss other LxyzTHW pages!
SQLite official website with full documentation (may be newer than the SQLite library that comes standard with AutoIt)

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