Updating mysql server
The My SQL Server option, which is highlighted, should say mysql-5.7.If it doesn't, press ENTER, then scroll down to mysql-5.7 using the arrow keys, and press ENTER again.(Bug #11758262, Bug #50439) See Section 220.127.116.11, “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.Once the option says mysql-5.7, scroll down on the main menu to Apply and press ENTER again. 5.7), which is not a supported upgrade path as documented by mysql.The easiest way around this is to upgrade mysql to 5.6 whilst still under 14.04. ) dumping all your databases; hostname # mysqldump --lock-all-tables -u root -p --all-databases then upgrading to mysql 5.6; hostname # apt-get install mysql-server-5.6 mysql-client-5.6 mysql-server-core-5.6 mysql-client-core-5.6 This way, all your databases are upgraded in place and (on my machines so far) entirely safely and transparently to 5.6.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.
So i have googled the solution and found the answer which worked for me at Digital Ocean Tutorial. I am pasting the particular portion of tutorial that worked for me .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.I had a problem - a had to update a column "rate" but if the existince or new value is greater then 5 this "5" will be finally value in 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.(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.