Issue in verifying two conditions!!

Hello All,

I am new to database and I need help for the following issue.

I have a table with column name code and I want to check two things for this column.
1.Check code1 in with few values.
2.check code1 not in few values

and I am joining this table with another table so that I can display few columns from these 2 tables.

And code is primary key in table1 and code1 is primary key in second table.

Thanks in advance for your help

Sachin