Petite Abeille wrote: > > what's the meaning of the first two numeral columns in > explain query plan? >
The columns of the explain query plan output are labeled by SQLite as: sqlite> .header on sqlite> .mode column sqlite> explain query plan select * from t; order from detail ---------- ---------- ---------- 0 0 TABLE t I believe the order is simply the order the tables are scanned. With the number incremented only when the scan is nested inside the other scan. Rows that are sequential with the same order number are executed sequentially rather than as a nested loop. I don't know what the from column is for. The source passes a variable called iFrom which is commented as "First unused FROM clause element". See http://www.sqlite.org/cvstrac/wiki?p=QueryPlans and http://www.sqlite.org/optoverview.html for some more info. There is a slide show from a presentation that Richard gave which explains how SQLite execute joins as nested for loops, but I can't find it now. HTH Dennis Cote _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
