Selection in 2 tables

[xcuseme]

I have 2 tables with addresses: t1 and t2. I need a selection of all addresses in table t1 except all addresses that are already in table t2.
I can compare the addresses by the postcode and housenumber fields.

I can get a selection of all adresses that are in both tables;

SELECT * FROM t1,t2
WHERE t1.Postcode = t2.pc
AND t1.Huisnummer = t2.nummer;

but how do I make a selection of all adresses in t1 except the once that I get listed with the SQL above?

Thanks

[cahva]

Use != (not) instead of = and that should do the trick if I understood you correctly.

SELECT t1.* FROM t1,t2
WHERE t1.Postcode != t2.pc
AND t1.Huisnummer != t2.nummer;

[tomhath]

Yipes. Think about the result set from that != join. What a mess.

Mysql documentation contains a nice explanation of how to get the effect of NOT EXISTS by using a LEFT JOIN.

SELECT t1.* FROM t1
LEFT JOIN t2
ON t1.Postcode = t2.pc
AND t1.Huisnummer = t2.nummer
where t2.pc is null

[xcuseme]

Thanks for the help, I got it.