1、查詢工資為2500到4000的人數 方式一: select count(*) from emp where sal>=2500 and sal<=4000; 方式二: select count(*) from emp where sal between 2500 and 4000; 2、查詢每個 ...
1、查詢工資為2500到4000的人數 方式一: select count(*) from emp where sal>=2500 and sal<=4000; 方式二: select count(*) from emp where sal between 2500 and 4000; 2、查詢每個 ...