The return value of query about lua-resty-mysql HOT 5 OPEN

@ZouDikai An empty result set is a totally valid result set and no error should get returned. I think you misunderstand the outcome of your SQL query.

from lua-resty-mysql.

How do I know whether the result set is empty?

from lua-resty-mysql.

@wowxunyl You'll get an empty table for that.

from lua-resty-mysql.

The result of sql below is empty in mysql client, but the lua table res deed has key(new_visitor, return_visitor) whose value I print using ngx.log is NULL. I really can't figure out why this happens.

SELECT 
    sum(new_visitor) as new_visitor, 
    sum(return_visitor) as return_visitor 
FROM analysis_visitor_dist 
WHERE 
    date>='20170408' 
AND 
    date<='20170407' 

from lua-resty-mysql.

@wowxunyl Maybe you mysql client is trying to do something clever. Not sure. This library just outputs whatever from the mysqld server responses.

from lua-resty-mysql.