Which two statements are true about WHERE and HAVING clauses? ()
A WHERE clause can be used to restrict both rows and groups.
B. A WHERE clause can be used to restrict rows only.
C. A HAVING clause can be used to restrict both rows and groups.
D. A HAVING clause can be used to restrict groups only.
E. A WHERE clause CANNOT be used in a query if the query uses a HAVING clause.
F. A HAVING clause CANNOT be used in subqueries.
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通过人体的工频电流超过()mA时,就有致命危险。
A. 5;
B. 25;
C. 50;
D. 200。
下列选项中,补贴收入不包括()等。
A. 按销量或工作量等依据国家规定的补助定额计算并按期给予的定额补贴
B. 属于财政扶持而给予的其他形式的补贴
C. 先征后返的增值税
D. 提供服务所获得的收入