Select one row element

You can select an entire row element from a collection into a row type host variable.

The INTO clause identifies a row variable in which to store the row element that is selected from the collection variable.

The following code fragment selects one row from the set_col column into the row type host variable a_row: 
EXEC SQL BEGIN DECLARE SECTION;
   client collection set(row(a integer) not null) a_set;
   row (a integer) a_row;
EXEC SQL END DECLARE SECTION;

EXEC SQL select set_col into :a_set from tab1
   where id_col = 17;
EXEC SQL select * into :a_row from table(:a_set);