There is a table called TBLPARTS P with a primary key P.PRIMLINK. It contains basic info about the part.
There is another table called TBLBARCODE B with the foreign key B.INVLINK=P.PRIMLINK that shows various part's barcode symbols used (vendor's, store's, etc).
There is another table called TBLLOCATION L with the foreign key L.INVLINK=P.PRIMLINK that shows various part's location and quantity information. Store 16 could have a part on the shelf, in stock, and on a quick-pick counter.
Last, I've got a table called TBLLOTS T with the foreign key T.INVLINK=P.PRIMLINK that is used for large spools of wire, rope, chain, etc. that are in some sort of partial state. Example: A customer buys 500-ft of cable on a 1000-ft spool, so that spool no longer has QTY=1. It gets converted into a lot of 1000 pieces, so that the result is 500 pieces. If another customer comes in and wants to buy 700-ft of cable, now we have 2 lots of the same part number: one at 500 pieces, and the other at 300 pieces. Are you following this?
I need to display just a little information about each of these tables.
I can join them using the INVLINK=PRIMLINK, filter them using STORE=16, but could still be looking at 2 to 4 records for a given barcode and 3 or 4 different lot numbers. When I do my join I could be looking at 16 duplicate looking rows for the same part number.
My SQL understanding is fine for straight-line SELECT, INSERT, and UPDATE commands, but I always seem to get really confused when it comes to JOIN statements.
What is a good way to rewrite this SELECT statement?
SELECT L.INVLINK, P.CATALOG, P.VENDOR, B.UPC, L.BIN_LOCATION, L.IN_STOCK-L.QTY_SHIPPED AS OnShelf, L.IN_STOCK, L.QTY_SHIPPED, L.LOC_TYPE FROM TBLLOCATION L LEFT JOIN TBLBARCODE B ON (L.INVLINK=B.INVLINK) LEFT JOIN TBLPARTS P ON (P.PRIMLINK=L.INVLINK) LEFT JOIN TBLLOTS T ON (L.INVLINK=T.INVLINK) WHERE L.STORE=16 AND I.VENDOR='TES' AND I.PRIMARY='P' ORDER BY I.VENDOR, I.CATALOG, L.BIN_LOCATION, L.INVLINK, B.UPC;
We are actually using an IBM DB2 database, but the SQL I am trying to learn is not anything focused on Microsoft SQL or IBM's SQL.