Updating a record in mysql
See Section 220.127.116.11, “Inno DB and FOREIGN KEY Constraints”. Records not matching the equijoin from table2 are marked with null.You cannot update a table and select from the same table in a subquery. This facilitates to update table1 column with expression whose corresponding value from table2 is returned as NULL It took me a few minutes to figure this out, but the syntax for UPDATING ONE TABLE ONLY using a relationship between two tables in My SQL 4.0 is actually quite simple:update t1, t2 set t1.field = t2.value where t1= t2.that; It should be noted that even simple applications of UPDATE can conflict with the 'safe mode' setting of the mysql daemon.
I was not able, using my SQL 4.1.1, to do this as a subquery: UPDATE Groups LEFT JOIN (SELECT Group Id, MIN(Val Within Group) AS base Val FROM Groups GROUP BY Group Id) AS Grp Sum USING (Group Id) SET Val Within Group=Val Within Group-base Val; Csaba Gabor UPDATE Syntax with "on-line" updating value limitations.That's how you can do ittable busstopsid | route | busstop | pos1 | 1 | A | 1 2 | 1 | B | 2 3 | 1 | C | 3 4 | 2 | C | 1 5 | 2 | D | 2 6 | 2 | A | 3 7 | 2 | E | 4 8 | 2 | F | 5 9 | 2 | G | 610 | 2 | H | 7Moving D, E, F, G To route 1 SET @pos=(SELECT max(t1.pos) FROM busstops t1 WHERE t1.route = 1 ); UPDATE busstops SET pos = ( SELECT @pos := @pos 1 ), route =1 WHERE id IN (5,7,8,9)I doubt this could be done otherwise since referencing the table you wish to update within the subquery creates circular references After DELETE or UPDATE i.e.when a row of a subset is lost/deleted/moved away from it, the whole subset will need to be reordered.Index hints (see Section 8.9.3, “Index Hints”) are accepted for PDF (US Ltr) - 27.2Mb PDF (A4) - 27.2Mb PDF (RPM) - 26.2Mb HTML Download (TGZ) - 6.5Mb HTML Download (Zip) - 6.5Mb HTML Download (RPM) - 5.6Mb Man Pages (TGZ) - 170.8Kb Man Pages (Zip) - 279.3Kb Info (Gzip) - 2.6Mb Info (Zip) - 2.6Mb My SQL Backup and Recovery My SQL NDB Cluster 7.2 My SQL Globalization My SQL Information Schema My SQL Installation Guide My SQL and Linux/Unix My SQL and OS X My SQL Partitioning My SQL Performance Schema My SQL Replication My SQL Restrictions and Limitations Security in My SQL My SQL and Solaris Building My SQL from Source Starting and Stopping My SQL My SQL Tutorial My SQL and Windows I will update field text in table Awith UPDATE `Table A`,`Table B`SET `Table A`.`text`=concat_ws('',`Table A`.`text`,`Table B`.`B-num`," from ",`Table B`.`date`,'/')WHERE `Table A`.`A-num` = `Table B`.`A-num`and come to this result Table A -------- -------------------------------------------- | A-num | text | | 1 | 24 from 03 08 2003 || 2 | 22 from 01 08 2003 / 23 from 02 08 2003 / | | 3 | || 4 | 25 from 04 08 2003 / 26 from 05 03 2003 / || 5 | | -------- -------------------------------------------- Update column in a table whose values are not found in another table. Many server admins default the My SQL daemon to 'safe mode'.If UPDATE gives an error like this:"You are using safe update mode and you tried to update a table without.."..it may be that your file must be edited to disable safemode. In order for the change in the file to take effect, you must have permission to restart mysqld in the server OS environment.There is a page in the online documentation that explains safe mode entitled 'safe Server Startup Script'.
Suppose you have a table where each row is associated with a certain group (For example, orders are associated with the customers placing them) where each item WITHIN the group has a distinct number (For example, each person my have a sequence of competition results - each person, therefore, has a 1st, 2nd, 3rd... If you would like to renumber items within their group so that each has the same baseline (say 0), here is an example way to proceed: Create TEMPORARY Table Groups (Id INTEGER AUTO_INCREMENT PRIMARY KEY, Name VARCHAR(31), Group Id VARCHAR(31), Val Within Group INTEGER); INSERT INTO Groups VALUES (null, "Davy", "Boy", 2); INSERT INTO Groups VALUES (null, "Mary", "Girl", 2); INSERT INTO Groups VALUES (null, "Bill", "Boy", 5); INSERT INTO Groups VALUES (null, "Jill", "Girl", -3); INSERT INTO Groups VALUES (null, "Fred", "Boy", 3);# Find the lowest value for each group CREATE TEMPORARY TABLE Group Sum AS SELECT Group Id, MIN(Val Within Group) AS base Val FROM Groups GROUP BY Group Id;# create an index so my SQL can efficiently match ALTER TABLE Group Sum ADD UNIQUE (Group Id);# finally, make the baseline adjustment UPDATE Groups LEFT JOIN Group Sum USING (Group Id) SET Val Within Group=Val Within Group-base Val; SELECT * FROM Groups;# 1 Davy Boy 0# 2 Mary Girl 5# 3 Bill Boy 3# 4 Jill Girl 0# 5 Fred Boy 1#Each group ("Boy", "Girl") now has a (lowest) Val Within Group entry of 0.
(Bug #11758262, Bug #50439) See Section 18.104.22.168, “Determination of Safe and Unsafe Statements in Binary Logging”, for more information.
If you access a column from the table to be updated in an expression, assignments are generally evaluated from left to right.
So, for the 3rd time, please run a SELECT * query with the exact same WHERE clause.
update (conn,'user2','pwd',data, where uname=uname1); is this correct?
DELETE FROM statement is used to delete records from database table.