AUTOCOMMIT是系统变量,在命令提示符下显示其值的语句是()
A. SHOW AUTOCOMMIT;
B. SHOW @@AUTOCOMMIT;
C. SELECT AUTOCOMMIT;
D. SELECT @@AUTOCOMMIT;
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假设Rno的值为"2020403001',则在下面的选择语句中,其在命令提示符下的计算结果是()CASE substring(Rno, 5, 3)WHEN'402'THEN'物理学'WHEN'403'THEN'应用数学'WHEN'408' THEN'计算机科学与技术'ELSE '汉语言文学'END
A. 物理学
B. 应用数学
C. 计算机科学与技术
D. 汉语言文学
有如下程序:DELIMITER $$CREATE PROCEDURE grade(IN score INT)BEGINDECLARE n INT;DECLARE r CHAR(2);CASE FLOOR(score/10)WHEN 10 THEN SET r='A';WHEN9 THEN SET r='A';WHEN8 THEN SET r='B';WHEN7 THEN SET r='C';WHEN6 THEN SET r='D';ELSE SET r='E';END CASE;SELECT score 成绩,r 等级;END$$在命令提示符下执行语句“CALL grade(85);”,则运行结果是()
A. +------+------+| 成绩 | 等级 |+------+------+| 85| B|+------+------+
B. +------+------+| 成绩 | 等级 |+------+------+| 85| A|+------+------+
C. +------+------+| score | r|+------+------+| 85| C|+------+------+
D. +------+------+| score | r|+------+------+| 85| B|+------+------+
有如下程序DELIMITER $$CREATE PROCEDURE fac(IN n INT)BEGINDECLARE s,i INT;SET s=1;SET i=n;WHILE i>0 DOSET s=s*i;SET i=i-1;END WHILE;SELECT n,s;END$$则在命令提示符下运行“CALL fac(5);”后的结果是()
A. +------+------+| n| s|+------+------+|5|15|+------+------+
B. +------+------+| n| s|+------+------+|5|10|+------+------+
C. +------+------+| n| s|+------+------+|5|20|+------+------+
D. +------+------+| n| s|+------+------+|5|120|+------+------+
在MySQL中,自定义函数在定义时,需要指定函数的返回值类型,如果自定义函数的类型为整型,则指定自定义函数返回值类型的语句是()
A. RETURN INT
B. RETURN INT;
C. RETURNS INT
D. RETURNS INT;