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@NogDogMar 07.2007 — #You can add to an existing value, something like:
@NogDogMar 07.2007 — #
I'm assuming (because it's how I would do it) that player_id would be defined as unique in the table definition (probably as the primary key), therefore making LIMIT 1 redundant. Besides, if it is [i]not[/i] unique, how would you know that the first record updated would be the correct one? (Which then goes to make it obvious why the whole thing would not make sense unless player_id [i]was[/i] unique.)@NogDogMar 07.2007 — #Eh...you still haven't convinced me. To each his own, I guess.
If the table is properly defined such that the column in the where clause is indexed as unique (e.g.: a primary key), then the DBMS already knows there can be only one match, and it will find it very quickly via the indexing. I just don't see enough potential gain (if any) to add the redundant limit clause to make me worry about changing my habits ("old dogs" and all that stuff).
updating mysql database…
Basically, I’ve built a little system, that records all poker tournament info.
I’m having difficulty with the leaderboard section.
Everytime you add a new player and prize money, I want it to add the prizemoney to the existing amount of prizemoney.
E.g. if John smith had 300 in prizemoney. I enter his name again, but this time entering 200… his total should now be 500.
However when I update it, instead of putting 500, it puts the amount that I just entered… 200.
is there a way of getting around this, possible something to do with the UPDATE statement?
MANY THANKS IN ADVANCE!!!
Rapidz.
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@NogDogMar 07.2007 — #You can add to an existing value, something like:[code=php]
$sql = "UPDATE table_name SET prizemoney = prizemoney + $prizeAmount WHERE player_id = $playerId";
[/code]0
@NogDogMar 07.2007 — #Sorry, it's a pet peeve...
[code=php][/QUOTE]
$sql = "UPDATE table_name SET prizemoney = prizemoney + $prizeAmount WHERE player_id = $playerId LIMIT 1";
[/code]
I'm assuming (because it's how I would do it) that player_id would be defined as unique in the table definition (probably as the primary key), therefore making LIMIT 1 redundant. Besides, if it is [i]not[/i] unique, how would you know that the first record updated would be the correct one? (Which then goes to make it obvious why the whole thing would not make sense unless player_id [i]was[/i] unique.)
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@NogDogMar 07.2007 — #If the table is properly defined such that the column in the where clause is indexed as unique (e.g.: a primary key), then the DBMS already knows there can be only one match, and it will find it very quickly via the indexing. I just don't see enough potential gain (if any) to add the redundant limit clause to make me worry about changing my habits ("old dogs" and all that stuff).