Updating rows using select into Live video hotchat without signing
A is a normal table, B is a temporary table: Worked in 4update A, B set A.population=B.pop_count where A.id=In version 5, however, the above query only updated one element while still matching "all"In 5 I had to do it like this:update A RIGHT JOIN B on A.id=set A.population=B.pop_count Updates all population counts correctly.[edit: RIGHT JOIN not LEFT JOIN...] Related to the post of Mohamed Hossam on May 9 2005 am A more general method to updtate more one row: UPDATE table SET f1='foo', f2= IF(f3=value,‘one’, IF(f3=value_bis,’two’,f2)) WHERE f5='afected' This set the values of field 'f2' according to the values of field 'f3' in the rows field f5 'afected'.Here is a way to use multiple tables in your UPDATE statement, but actually copying one row values into the other, meaning, we're using the same table: UPDATE jobs AS to Table, jobs AS from Table SET to Table.job_type_id = from Table.job_type_id, to Table.job_company_id = from Table.job_company_id, to Table.job_source = from Table.job_source, WHERE (to Table.job_id = 6) AND (from Table.job_id = 1)--------------Pretty cool.order by recno desc limit 1You can also accomplish the same by the following query :update t1 , (select id ,max(recno) as recno from t1 where id=8 group by recno) ttset t1.c1 = ' NO'where tt.id=t1and t1.recno=tt.recno Comments are welcome.The @value := col will always evaluate to true and will store the col value before the update in the @value variable.(Bug #11758262, Bug #50439) See Section 188.8.131.52, “Determination of Safe and Unsafe Statements in Binary Logging”, for more information.
There is a page in the online documentation that explains safe mode entitled 'safe Server Startup Script'.
Ideal when writing a script is just too much effort.
Sometimes you have a lot of processes that could be updating a column value in a table. ID=54321 Here's a workaround for the update/subquery/cant do self table "bug"Senario is, ID 8 has multiple records, only the last (highest) record needs to be changedupdate t1 set c1 = ' NO'where id='8'order by recno desc limit 1I would prefer update t1 set c1=' NO' WHERE ID=8 AND RECNO = (SELECT MAX(RECNO) FROM T1 WHERE ID=8)But that's not currently allowed If you want to update a table based on an aggregate function applied to another table, you can use a correlated subquery, for example: UPDATE table1 SET table1field = (SELECT MAX(table2.table2field) FROM table2 WHERE table1.table1field = table2.table2field)This can be helpful if you need to create a temporary table storing an ID (for, say, a person) and a "last date" and already have another table storing all dates (for example, all dates of that person's orders).
when a row of a subset is lost/deleted/moved away from it, the whole subset will need to be reordered.
This can be done similarily : SET @pos=0; UPDATE busstops SET pos = ( SELECT @pos := @pos 1 ) WHERE route = 1 ORDER BY pos ASCChris H (chansel0049) I experienced a weird issue converting from 4 to 5.