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Björn Norén
9,569 PointsMysql Addition & Subtraction
Hi! I'm working with a fictive Music Shop were the shop needs to order instruments from a deliver company when they are out of guitars, pianos etc. And I realized I really don't know how to use addition ( for ordering ) and subtraction ( when a instrument is being sold ).
I guess I need a column for quantity? Like:
Instrument_ID : D1445 Quantity : 26 ( for example )
Am I on the right track? Could someone share a brief explanation on how I should move on? Thank you very much, sorry for my bad english.
1 Answer
Henrik Hansen
23,176 PointsYes, that is right. You can use the current value in a field in your SQL command.
UPDATE table_name
SET quantity = quantity - 1
WHERE id = 'D1445'
Björn Norén
9,569 PointsWow, thanks :) That was very easy to understand!
Jennifer Nordell
Treehouse TeacherJennifer Nordell
Treehouse TeacherJust a note: In that entire block of text I only saw one spelling error and one misplaced comma :) Trust me when I tell you that there are native English speakers that don't write as well as you do.