[thelist] MySQL how to table1.id not in table2.whatever

rudy r937 at interlog.com
Tue Feb 18 16:16:01 CST 2003


>  I'd like to see which products are "orphans" and
>  aren't listed in pro_gal_tbl.product_id

   select product_tbl.id
        , product_tbl.name
     from product_tbl
   left outer
     join pro_gal_tbl
       on product_tbl.id
        = pro_gal_tbl.product_id
    where pro_gal_tbl.product_id is null

this is a left join, which by itself returns both matched and unmatched rows
from the left table, and then checking for null in the unmatched column
gives you the orphans

> Also, any recommended overviews of JOINS and what have you?

http://www.w3schools.com/sql/sql_join.asp


rudy




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