Q: 153 What is true regarding subqueries?A. The inner query always sorts the results of the outer query.
B. The outer query always sorts the results of the inner query.
C. The outer query must return a value to the inner query.
D. The inner query returns a value to the outer query.
E. The inner query must always return a value or the outer query will give an error.Answer: D没有看懂这几个选项的意思，明白sub query，但是inner query、outer query是啥意思？
B. The outer query always sorts the results of the inner query.
C. The outer query must return a value to the inner query.
D. The inner query returns a value to the outer query.
E. The inner query must always return a value or the outer query will give an error.Answer: D没有看懂这几个选项的意思，明白sub query，但是inner query、outer query是啥意思？
()里面的select t2.name from t2 where t2.did=t1.did就是inner outer
而()外面的select (select t2.name from t2 where t2.did=t1.did) from t1 就属于outer query