Hi, look on this, only simple sample, by if join count increase you will see difference faster. Also faster if you join by few fields not only one. At first look you see clearly where is filter and where is join condition. And then you can simply analyse if query use indexes on joined fields and if it is true you go forward and you analyze if filter “where” can be also indexed
SELECT ... FROM TABLE_A A INNER JOIN TABLE_B B ON A.ID=B.ID WHERE A.FIELDX>5 and SELECT ... FROM TABLE_A A, TABLE_B B WHERE A.ID=B.ID AND A.FIELDX>5 regards, Karol Bieniaszewski From: [email protected] [firebird-support] Sent: Monday, September 25, 2017 7:02 PM To: [email protected] Subject: Re: [firebird-support] Huge performance different from FB 2.5.2 vs FB 3.02 Karol: Not to highjack the thread, but a question. You stated: > this is terible to read. Please change join style to explicite join style > > instead SELECT .. FROM TABLE_A A, TABLE_B B WHERE A.ID=B.ID > write SELECT .. FROM TABLE_A A INNER JOIN TABLE_B B ON A.ID=B.ID I'm not a DB expert, only as I have to but I read the first line easier than the second line, but not without much difference. Why do you state it is terrible? Ed Dressel
