SQL Tutorial : COMPLEX VIEW
Let's learn about next topic: COMPLEX VIEW
COMPLEX VIEWS:
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- CREATE OR REPLACE VIEW EMP_DEPTV
AS
SELECT E.LAST_NAME,D.DEPARTMENT_NAME
FROM COPY_EMP E,COPY_DEPT D
WHERE E.DEPARTMENT_ID=D.DEPARTMENT_ID
- CREATE OR REPLACE VIEW EMPV
AS
SELECT DISTINCT EMPLOYEE_ID EID ,LAST_NAME LNAME ,SALARY SAL ,JOB_ID
FROM COPY_EMP
- NAMED SUB-QUERY IN THE FROM CLAUSE IS CALLED AS A INLINE
VIEW.
USAGE:
1.TOP-N-ANALYSIS
2.DISPLAY DATA FROM MULTIPLE TABLES
USING SUB-QUERY
- DROPING VIEW:
DROP VIEW EMPV
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