Host variable field names

If the field names of the row column and the row variable are different, you must specify the field names of the row host variable. For example, if the last SELECT statement in the following example referenced field names x and y instead of the field names of a_row, it would generate a runtime error.
EXEC SQL BEGIN DECLARE SECTION;
   row (a integer, b float) a_row;
   int i;
   double f;
EXEC SQL END DECLARE SECTION;

EXEC SQL create table tab (row_fld(x integer, y float));
EXEC SQL insert into tab values (’row(9, 3.34e7)’);
EXEC SQL select * into a_row from tab;
EXEC SQL select a, b into :i, :f from table(:a_row);