left outer join and where clause for table on right
i want to join two tables a and b, where a is a must and b is an optional resultset. when i use left outer join from a to b, i want to achieve :
1- select one column from a, two columns from b (not join columns)
2- even if theres no mathces on join column return data from a .
3- if there's a match apply where criteria on column from b (optional table)
so how can i avoid no_data_found in this case ? when i apply where criteria to b then it doesnt return data from a, which is a must.