A. You have too many tables.
B. Your tables are too long.
C. Your tables have difficult names.
D. You want to work on your own tables.
E. You want to use another schema's tables.
F. You have too many columns in your tables.

A. A single row subquery can retrieve only one column and one row.
B. A single row subquery can retrieve only one row but many columns.
C. A multiple row subquery can retrieve multiple rows and multiple columns.
D. A multiple row subquery can be compared by using the “>” operator.
E. A single row subquery can use the IN operator.
F. A multiple row subquery can use the “=” operator.