写出下面SQL语句的功能SELECT * FROM student WHERE YEAR(birthday)=1997 OR YEAR(birthday)=1999;
写出下面SQL语句的功能SELECT * FROM student WHERE YEAR(birthday) in(1997,1999) ;
写出下列SQL语句的功能SELCET COUNT(DISTINCT 家庭住址) FROM 档案表 ;
写出下列SQL语句的功能SELECI * FROM 产品 WHERE 单价>600 AND (名称='主机板' OR 名称='硬盘');