Getting data from one table for comparison with another table in mysql

Question

SELECT * FROM `room_type` WHERE h_id='$h_id' AND `rt_oc` >= '$tperson' AND `rt_num` < (SELECT COUNT(`check_out`) FROM `room_info` WHERE `h_id`='$h_id' AND LEFT JOIN `room_type` ON room_type.rt_type=room_info.room_type)); 

Here I want to select data from table1, where it will compare the value of a column from table2, the same amount of column value.

Answer 1

 WHERE `h_id`='$h_id' AND LEFT JOIN 

This will not work, you need to update the helper request as follows:

 (SELECT COUNT(`check_out`) FROM `room_info` LEFT JOIN `room_type` ON room_type.rt_type=room_info.room_type WHERE `h_id`='$h_id') 

By the way, you have )); at the end of the request - check it.

 SELECT * FROM `room_type` WHERE h_id='$h_id' AND `rt_oc` >= '$tperson' AND `rt_num` < (SELECT COUNT(`check_out`) FROM `room_info` LEFT JOIN `room_type` ON room_type.rt_type=room_info.room_type WHERE `h_id`='$h_id') 

Answer 2

Your request should be as follows:

 SELECT * FROM `room_type` WHERE h_id='$h_id' AND `rt_oc` >= '$tperson' AND `rt_num` < (SELECT COUNT(`check_out`) FROM `room_info` LEFT JOIN `room_type` ON room_type.rt_type=room_info.room_type WHERE `h_id`='$h_id'));