How to use Left Join in subquery SQL Server? - sql

Question

I am trying to use left join in subquery in SQL Server. My query looks fine to me but it gives syntax error.
This is my query:
(
SELECT
FK_OrderNo AS LHNo, VendorName AS LHVendor
FROM
tbl_ShipmentAPAR
LEFT JOIN
tbl_vendors ON FK_VendorID = VendorID
WHERE
FK_ServiceID = 'LH'
) LHBase ON PK_OrderNo = LHNo
LEFT JOIN
(SELECT
FK_OrderNo AS DANo,
VendorName AS DAVendor
FROM
tbl_ShipmentAPAR
LEFT JOIN
tbl_vendors ON FK_VendorId = VendorId
WHERE
FK_ServiceId = 'DA') DABase ON PK_OrderNo = DANo
This is the error I'm getting:
This is my table structure:
CREATE TABLE tbl_ShipmentAPAR
(
VendorID int PRIMARY KEY,
VendorName varchar(200),
FK_OrderNo int
)
CREATE TABLE tbl_vendors
(
FK_VendorID int,
FOREIGN KEY (FK_VendorID) REFERENCES tbl_ShipmentAPAR(VendorID),
FK_ServiceID varchar(200)
)
INSERT INTO tbl_ShipmentAPAR VALUES (1, 'John',123)
INSERT INTO tbl_vendors VALUES (1,'LH')

Answer 1

As #Chris mentioned, the query is bit incomplete. I guess you are trying to do something like this:
SELECT * FROM /*--> Added new */
(
SELECT
FK_OrderNo AS LHNo, VendorName AS LHVendor
FROM
tbl_ShipmentAPAR
LEFT JOIN
tbl_vendors ON FK_VendorID = VendorID
WHERE
FK_ServiceID = 'LH'
) LHBase
LEFT JOIN
(SELECT
FK_OrderNo AS DANo,
VendorName AS DAVendor
FROM
tbl_ShipmentAPAR
LEFT JOIN
tbl_vendors ON FK_VendorId = VendorId
WHERE
FK_ServiceId = 'DA') DABase ON LHBase.LHNo = DABase.DANo /* -->Modified PKOrder no to LHNo because PKOrder no doesn't exist in either of the sub-queries */
This query worked for me. Comment to this answer if something must be changed.