SQL语句快速入门.docx

Select*fromtablename

SQLselect*fromemployees;

Selectselectlistfromtablename

SQLselectemployee_id,first_namefromemployees;

Selectdistinct…fromtablename

SQLselectdistinctmanager_idfromemployees;

||连接符使用以及加减乘除以及括号的使用

SQLselectemployee_id,first_name||.||last_name,salary*(1+0.1)/100,manager_id

2 fromemployees;

+-做正负号使用

SQLselect -salary fromemployees;

,,,=,!=等比较操作符

SQLselect * fromemployeeswheresalary13000;SQLselect * fromemployeeswheresalary13000;SQLselect * fromemployeeswheresalary13000;SQLselect * fromemployeeswheresalary=13000;

In

SQLselect -salary fromemployeeswhereemployee_idin(100,101,102);

SQLselect -salary fromemployeeswhereemployee_idin(selectemployee_idfrom employees);

notin

SQLselect -salary fromemployeeswhereemployee_idnotin(100,101,102);

Any(比任意一个都)

select* fromemployeeswhereemployee_idany(100,101,102);

some是SQL-92标准的any的等效物

select* fromemployeeswhereemployee_idany(100,101,102);

all（比所有的都）

select* fromemployeeswhereemployee_idall(100,101,102);

betweenand

select* fromemployeeswhereemployee_id between100and102;

notbetweenand

select* fromemployeeswhere employee_idnotbetween100and102;

逻辑操作符

And和or

select* fromemployeeswhere employee_id100and employee_id1000;select* fromemployeeswhere employee_id100or employee_id1000;

OrderbyDesc

select* fromemployeeswhereemployee_id between100and102orderbyemployee_iddesc;

Asc

Asc

select* fromemployeeswhereemployee_id between100and102 orderby

employee_idasc;

dual哑元表没有表需要查询的时候可以用它

selectsysdatefromdual;

select1*2*3*4*5fromdual;