单项选择题 Given that tables T1 and T2 contain the following rows: Table T1: C1 C2 1 4 1 3 1 2 Table T2: C1 C2 1 1 1 2 1 3 Which of the following queries will return only those rows that exist in both T1 and T2?（）

单项选择题 Which kind of non-sourced UDF can be created so that it only returns a single value?（）

单项选择题 Given the following stored procedure:CREATE PROCEDURE increase_salary ( IN p_workdept CHAR(6), OUT p_sum DECIMAL(9,2) ) SET p_sum = (SELECT SUM(salary) FROM employee WHERE workdept=p_workdept);How can this stored procedure be called from the Command Line Processor?（）