Error address not on / off?

[phongvucba]

Thank pro! I will check my fuction. Oh no, that"s my job! .
I have some questions to answer, expect people to help me, I am new! Sad
What is the difference between an Event-based and an Event script?
-I have the following function:
"Query = 'SELECT name FROM objects WHERE tagcache ==? AND datahex ==?'
 If table.maxn (db: getall (query, 'PB_T1', '01')) == 0 then
   Grp.write (`3/1/2 ', true)
 End "
So what does this query do? And what does the "if" command do?
Thank pro!