deleting forum replies

[dadamssg]

im developing a forum and am going to create a cron job to delete threads every so often. but i also want the replies to be deleted as well, how would i go about checking the number that the replies correspond to the thread ID and delete all of them. keep in mind they are in seperate tables, threads and replies. basically i don't want to keep the replies if the thread has been deleted.

[daanoz]

first do a select for the ones you are about to delete

 

Select ThreadId FROM ThreadTable WHERE timestamp < 2008-01-01 12:12:12

 

then delete replies

DELETE FROM ReplyTable WHERE ThreadId IN (1,2,3,4,5,6)

 

then delete threads

DELETE FROM ThreadTable WHERE timestamp < 2008-01-01 12:12:12

[dadamssg]

can you explain what this part does or means?

 

WHERE ThreadId IN (1,2,3,4,5,6)

[daanoz]

sure,

 

it like a conditional match.

 

All records which have a treadid 1, 2, 3, 4, 5, 6 will get deleted

 

for example, you have 6 threads, which have id's 1,2,3,4,5,6

 

 

then you call

DELETE FROM ReplyTable WHERE ThreadId IN (2,4,6)

 

only the replies from the 2nd, 4th and 6th thread will be deleted

 

http://www.w3schools.com/sql/sql_in.asp

 

Cheers

[dadamssg]

i guess im not fully understanding...how do you get the selected rows from

 

Select ThreadId FROM ThreadTable WHERE timestamp < 2008-01-01 12:12:12

 

and put those in

 

DELETE FROM ReplyTable WHERE ThreadId IN (1,2,3,4,5,6)

 

do you due some sort of embedding? the the

ThreadId IN (1,2,3,4,5,6)

part?