Oracle multiple processes updating same table blackwhite dating
What I'm doing here is copying the information I need from the row where job_id=1 to the row where job_id=6, on the same table.
Adam Boyle's commment above was just what I was trying to do, update one table based on a relationship between that table and another.
(Bug #11758262, Bug #50439) See Section 184.108.40.206, “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.
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).
Only the partitions (or subpartitions) listed are checked for matches, and a row that is not in any of these partitions or subpartitions is not updated, whether it satisfies the clause, are flagged as unsafe for statement-based replication.
(This is because the order in which the rows are updated determines which rows are ignored.) Such statements produce a warning in the error log when using statement-based mode and are written to the binary log using the row-based format when using mode.
Notes: That index addition is necessary because on larger tables my SQL would rather die than figure to (internally) index a single column join.If you add new entries or move stops from one route to another you will most likely want to increment the position of the busstop within this route.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.If you wish to use an increment based on subset of a table you may combine UPDATE with Variables:e.g.A table that contains entries of different categories, in which an internal order needs to represented ( lets say a table with busstops on different routes).