子句在MySQL中离开的地方

Question

Hello guys may I ask where I can put the where clause in a Left Join here on query

SELECT en.`transid`, en.`transdate`, 
                CONCAT(userlist.lname, ', ', userlist.fname, ' ', userlist.mname) AS sender_name, 
                CONCAT(userlist1.lname, ', ', userlist1.`fname`, ' ', userlist1.`mname`) AS receiver_name,
                en.`document_num`, doctype.`document_type`, vendor.`vendor_name`, acknowledge.`status`
                FROM `tbl_encode_transmittal` en 
                LEFT JOIN `tbl_acknowledgetransmittal` acknowledge ON en.`transid` = acknowledge.`transid`
                LEFT JOIN tbl_userlist userlist ON userlist.userid = en.sender_id
                LEFT JOIN tbl_userlist userlist1 ON userlist1.userid = en.`receiver_id`
                LEFT JOIN `tbl_doctype` doctype ON doctype.`doc_id` = en.`doctype_id`
                LEFT JOIN tbl_vendor vendor ON vendor.`vendor_id` =  en.vendor_id

This is the Where Clause that I will include in my query:

WHERE userlist1.userid = 'admin'

Answer 1

You can put it at the end, like others said, or as an "AND" like this:

SELECT en.`transid`, en.`transdate`, 
                CONCAT(userlist.lname, ', ', userlist.fname, ' ', userlist.mname) AS sender_name, 
                CONCAT(userlist1.lname, ', ', userlist1.`fname`, ' ', userlist1.`mname`) AS receiver_name,
                en.`document_num`, doctype.`document_type`, vendor.`vendor_name`, acknowledge.`status`
                FROM `tbl_encode_transmittal` en 
                LEFT JOIN `tbl_acknowledgetransmittal` acknowledge ON en.`transid` = acknowledge.`transid`
                LEFT JOIN tbl_userlist userlist ON userlist.userid = en.sender_id
                LEFT JOIN tbl_userlist userlist1 ON userlist1.userid = en.`receiver_id` AND userlist1.userid = 'admin'
                LEFT JOIN `tbl_doctype` doctype ON doctype.`doc_id` = en.`doctype_id`
                LEFT JOIN tbl_vendor vendor ON vendor.`vendor_id` =  en.vendor_id

Answer 2

It does not matter what join type you use, the where clause follows the from clause and the join conditions:

FROM `tbl_encode_transmittal` en 
                LEFT JOIN `tbl_acknowledgetransmittal` acknowledge ON en.`transid` = acknowledge.`transid`
                LEFT JOIN tbl_userlist userlist ON userlist.userid = en.sender_id
                LEFT JOIN tbl_userlist userlist1 ON userlist1.userid = en.`receiver_id`
                LEFT JOIN `tbl_doctype` doctype ON doctype.`doc_id` = en.`doctype_id`
                LEFT JOIN tbl_vendor 4vendor ON vendor.`vendor_id` =  en.vendor_id
WHERE userlist1.userid = 'admin'

Answer 3

You put them after the FROM and JOIN clauses like normal.

SELECT *
FROM table1 t1
JOIN table t2 ON t1.id = t2.fk
WHERE t1.whatever = "whatever"