Situation

table1 has 2 columns: userid and requiredInfo
It will have an entry for every user

table2 has 2 columns: userid and optionalInfo
It will have entries for some users but not others

Problem:
need a statement that returns either

userid, table1.requiredInfo, table2.optionalInfo
--if table2 has an entry
OR
userid, table1.requiredInfo, null
--if table2 does not have an entry