Question

Database A contains table X

Database B contains tables Y and Z

A.X contains fields order_number and dude

B.Y contains fields order, dude_number
B.Z contains fields other_dude_number and dude_type

I want A.X.dude to update to B.Y.dude_number based on: (B.Y.order = A.X.order_number) AND ((B.Z.other_dude_number = B.Y.dude_number) AND (B.Z.dude_type = 6))

I’ve been pumping out mySQL queries for two hours to try and get this to work. I’m almost sure I need a UNION in there, somewhere, but I’m not familiar enough with UNION to use it.

Answer 1

UPDATE A.X
  JOIN B.Y ON Y.`order` = X.order_number
  JOIN B.Z ON Z.other_dude_number = Y.dude_number
SET      X.dude = Y.dude_number
WHERE    Z.dude_type = 6