The Little Guy Posted May 15, 2009 Share Posted May 15, 2009 I am building a "Fake" bank, when a user signs up, he/she starts out with a $500,000 loan from the bank. He/she then can buy or sell stuff, and each transaction will be stored in a table in the database. I am wondering, will I get an accurate user balance if I use mysql SUM on ALL of the users transactions? SELECT SUM(`amount`) as loanSum FROM bank WHERE owner = '$this->owner' AND (type='l' OR type='d' OR type='w') type l = loan type d = deposit type w = withdrawal (this contains a negative value such as: -400) Link to comment https://forums.phpfreaks.com/topic/158318-a-bank/ Share on other sites More sharing options...
.josh Posted May 16, 2009 Share Posted May 16, 2009 yes. also, instead of all of those OR's, you can do SELECT SUM(`amount`) as loanSum FROM bank WHERE owner = '$this->owner' AND type IN ('l','d','w') Link to comment https://forums.phpfreaks.com/topic/158318-a-bank/#findComment-835080 Share on other sites More sharing options...
Ken2k7 Posted May 16, 2009 Share Posted May 16, 2009 What other types are there? Link to comment https://forums.phpfreaks.com/topic/158318-a-bank/#findComment-835082 Share on other sites More sharing options...
.josh Posted May 16, 2009 Share Posted May 16, 2009 type r = rob lol. Link to comment https://forums.phpfreaks.com/topic/158318-a-bank/#findComment-835086 Share on other sites More sharing options...
Ken2k7 Posted May 16, 2009 Share Posted May 16, 2009 That was a good one. Just noticed. Can you use $this->owner inline in the string like that? Link to comment https://forums.phpfreaks.com/topic/158318-a-bank/#findComment-835087 Share on other sites More sharing options...
The Little Guy Posted May 16, 2009 Author Share Posted May 16, 2009 Just noticed. Can you use $this->owner inline in the string like that? Yes! I didn't think it would work either Link to comment https://forums.phpfreaks.com/topic/158318-a-bank/#findComment-835094 Share on other sites More sharing options...
trq Posted May 16, 2009 Share Posted May 16, 2009 Complex variables should be surrounded by {} braces. SELECT SUM(`amount`) as loanSum FROM bank WHERE owner = {'$this->owner'} AND type IN ('l','d','w') Link to comment https://forums.phpfreaks.com/topic/158318-a-bank/#findComment-835096 Share on other sites More sharing options...
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