Updating table rows in php 4

If you want to return the value before you updated it without using a seperate select (which unless you lock the table could return a different value than is updated) then you can use a mysql variable like this:update some_table set col = col 1 where key = 'some_key_value' and @value := col The @value := col will always evaluate to true and will store the col value before the update in the @value variable. Additional information on My SQL correlated subqueries is at UPDATE can apparently be used to implement a semaphore (pardon my pseudocode):while TRUE The code above waits until the semaphore is "cleared" (value = 0) and then "sets" it (value = 1).You could then do select @value;in order to see what the value was before you updated it My SQL uses Watcom (Oracle) syntax for UPDATE, so it's possible to write something like:update Table1 t1 join Table2 t2 on t1. When done, you "clear" the semaphore by UPDATE table SET value = 0 WHERE name = 'name' The assumption is that the UPDATE is "atomic" in that no concurrent access by another process can occur between testing and setting the value field.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.

2 | 22 from 01 08 2003 / 23 from 02 08 2003 / | | 3 |

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