Oracle Basic Query Content collation

Source: Internet
Author: User

Tags: duplicate desc employee IMA User data dictionary data src share picture

Clear Screen

Host CLS;

View Current User

Show user;

Tables under the current user

SELECT * from tab;

tab data Dictionary

DESC EMP;

Find information for all employees

SELECT * from EMP;

Querying by Column name

Select Empno,ename,job,sal from EMP;

Query employee number, name, salary, annual salary

Select empno,ename,sal,sal*12 from EMP;

Query employee number, name, salary, annual salary, annual income

Select Empno Employee number, ename name, Sal monthly salary, sal*12 annual salary, Comm Bonus, Sal*12+comm annual income from EMP;

Select Empno Employee number, ename name, Sal monthly salary, sal*12 annual salary, NVL (comm,0) bonus, SAL*12+NVL (comm,0) annual income from EMP;

Select Comm is empty

Select*from EMP where comm is null;

Distinct to remove duplicate records

Select Deptno from EMP;

SELECT DISTINCT deptno from EMP;

Select Job from EMP;

SELECT distinct job from EMP;

SELECT distinct deptno,job from EMP; Deptno and job combinations are not duplicated.

Select concat (' Hello ', ' world ') from EMP;

Select 3+2 from dual;

Select ' Hello ' | | ' World ' from dual;

Select Ename| | ' The salary is ' | | Sal

Oracle Basic Query Content collation

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