MYSQL - MULTIPLE SET VALUES IN ONE UPDATE STATEMENT USING 2 TABLES AS REFERENCE AND STORING VALUES IN ONE OF THOSE TABLES WITH A SPECIFIC LOGIC. Hello people, A problem came up by making an UPDATE. The example issue is as follows: CURRENUSRTABLE +------------+-------+ | ID | STATE | +------------+-------+ | 123 | 3 | | 456 | 3 | | 789 | 3 | +------------+-------+ HISTORYTABLE +------------+------------+-----+ | ID | TRDATE | ACT | +------------+------------+-----+ | 123 | 2013-11-01 | 5 | | 456 | 2013-11-01 | 5 | | 789 | 2013-11-01 | 5 | | 123 | 2013-11-02 | 4 | | 456 | 2013-11-02 | 4 | | 789 | 2013-11-02 | 4 | | 123 | 2013-11-03 | 3 | | 456 | 2013-11-03 | 3 | | 789 | 2013-11-03 | 3 | +------------+------------+-----+ I'm using these variables: @BA=3, @DE=5, @BL=4, What I'm trying to do is an update on CURRENUSRTABLE.STATE using HISTORYTABLE.ACT with the following logic: STATE value will be updated as ACT value, except when STATE value is 4 and ACT is 3, then STATE will be 5 I made this statement: UPDATE CURRENUSRTABLE RIGHT OUTER JOIN HISTORYTABLE ON HISTORYTABLE.ID=CURRENUSRTABLE.ID SET CURRENUSRTABLE.STATE= ( SELECT CASE HISTORYTABLE.ACT WHEN @DE THEN @DE WHEN @BL THEN @BL WHEN @BA THEN CASE CURRENUSRTABLE.STATE WHEN @BL THEN @DE ELSE @BA END END ORDER BY HISTORYTABLE.TRDATE,FIELD(HISTORYTABLE.ACT,@DE,@BL,@BA) ) WHERE HISTORYTABLE.TRDATE BETWEEN '2013-11-01' AND '2013-11-01' I'm intentionally using "RIGHT OUTER JOIN" and "HISTORYTABLE.TRDATE BETWEEN" because I'd like to change the values in CURRENUSRTABLE using a timeframe of more than one day. If I execute this statement many times using only one day (i.e. "BETWEEN '2013-11-01' AND '2013-11-01'" and then "BETWEEN '2013-11-02' AND '2013-11-02'"... etc ) it works perfectly, but if it is executed using the dates "BETWEEN '2013-11-01' AND '2013-11-03'" the results on CURRENUSRTABLE.STATE are 3, which is wrong, it should be 5. I think the problem relies on "CASE CURRENUSRTABLE.STATE" when uses "HISTORYTABLE.TRDATE BETWEEN '2013-11-01' AND '2013-11-03'", because it reads the STATE 9 times which has not been commited yet until the statement ends. Query OK, 9 rows affected (0.00 sec) Rows matched: 9 Changed: 9 Warnings: 0 Maybe the solution is very simple, but unfortunately I've not much practice on MySQL since I've worked with it less than 2 months :) Is there any suggestions to solve this issue? PD: MySQL version is 4.1.22, I know is very old an EOL, unfortunately I have to make these statements on this version. Thanks!