SQL BASICS

 create table 


EMP AS SELECT * FROM SCOTT.EMP;




SELECT * FROM EMP;



SELECT ENAME,JOB,DEPTNO


FROM EMP;



SELECT * 

FROM EMP


WHERE DEPTNO IN (10,20);



SELECT *

FROM EMP



-- < ,> ,>=,> OR =,< OR =,<=,<>,!=



SELECT * 

FROM EMP


WHERE COMM IS NULL;



SELECT * 

FROM EMP


WHERE COMM IS NOT NULL;



SELECT *

FROM EMP


WHERE JOB NOT IN('MANAGER')


SELECT *

FROM EMP

WHERE JOB  IN('MANAGER')



----SORTING (ASC,DESC)


SELECT *


FROM EMP


WHERE JOB = 'MANAGER' ORDER BY HIREDATE DESC;



----MAX,MIN,COUNT,SUM,AVG





SELECT SUM(SAL),DEPTNO

FROM EMP

GROUP BY DEPTNO;



SELECT AVG(COMM),SUM(SAL),DEPTNO

FROM EMP

GROUP BY DEPTNO;



SELECT * FROM EMP;



---FOR NON NULL VALUES COLUMNS


SELECT COUNT(JOB) AS COUNT,JOB

FROM EMP

GROUP BY JOB 

ORDER BY 2;


SELECT COUNT(*) AS COUNT,JOB

FROM EMP

GROUP BY JOB 

ORDER BY 2;



----FILTERING (WHERE,HAVING)


SELECT COUNT(*) AS COUNT,JOB     ----4

FROM EMP                         ----1

WHERE JOB <> 'PRESIDENT'     --------2

GROUP BY JOB                 --------3

ORDER BY 2;                 ---------5



SELECT MAX(SAL),ENAME

FROM EMP


GROUP BY ENAME


----COUNT OF EMPLOYEES IN EACH DEPARTMENT 


SELECT COUNT(JOB),DEPTNO


FROM EMP


GROUP BY DEPTNO



--HOW MANY JOBS IN EACH DEPT




SELECT COUNT(*),DEPTNO,JOB


FROM EMP


GROUP BY DEPTNO,JOB ORDER BY DEPTNO



---HOW MANY EMPLOYEES IN EACH JOB


SELECT COUNT(*) 

FROM EMP 


GROUP BY JOB;



--HOW MANY JOBS IN EACH DEPART




SELECT COUNT(*),DEPTNO,JOB

FROM EMP


GROUP BY DEPTNO,JOB


---CREATING TABLES 




























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