Question

Using the products table as the master, I want to list all products. If the product has a description in table prod_desc, I want to pull it in. Also, if the product has a manufacturer description, I want to pull it in. I want the product row to display once, whether it has a prod description, manufacturer description, one, both or neither.

A left join works well for one external lookup, but the second one messes it up.

SELECT * FROM t1
LEFT JOIN t3 ON t1.a=t3.a
LEFT JOIN t2 ON t1.b=t2.b

Answer 1

It looks to me like your “select *” might be the issue. but I cannot tell for sure what you mean by “mess it up.” Try to select only what you want, and see if that solves it.

For example,

SELECT a, b, c, d, e
FROM t1
  LEFT JOIN t3 
    ON t1.a = t3.a
  LEFT JOIN t2
    ON t1.b = t2.b