Getting ora-01427 single-row subquery while exporting data

Hi All,

I am getting ora-01427 single-row subquery returns more than one row error while I export data from SQL Developer.

I run the query in SQL Developer, I get some output, and when I export that output to an xls sheet, I am getting the above error. My query structure is like below:

select column1,

         column2,

         (select statement) column 3,

         column4,

         (select statement) column5,

         (select statement) column6,

         (select statement) column7

from table1,table2,(select statement) ResultSet

where column3 in (val1,val2,val3) and column3 is null;

Any kind of help or suggestions provided is highly appreciated.

Thanks,

RC