DML, . :
UPDATE Salesown
SET city = 'Palo Alto'
WHERE snum = 1004;
. , UPDATE
UPDATE Salesown
SET comm =.20
WHERE snum = 1004;
, comm Salesown. , , .
21.
, , . . , :
;
, .
, , . , . , "" . , - , .
, , . SQL , . Londonstaff:
CREATE VIEW Londonstaff
AS SELECT *
FROM Salespeople
WHERE city = 'London';
SELECT *
FROM Londonstaff
WHERE comm >.12;
, :
SELECT *
FROM Salespeople
WHERE city = 'London' AND comm >.12;
, , . , . , , (CREATE) :
CREATE VIEW Ratingcount (rating, number)
AS SELECT rating, COUNT (*)
FROM Customers
GROUP BY rating;
, rating. , , - , :
SELECT *
FROM Ratingcount
WHERE number = 3;
, , :
SELECT rating, COUNT (*)
FROM Customers
WHERE COUNT (*) = 3
GROUP BY rating;
. , COUNT (), . , , :
|
|
SELECT rating, COUNT (*)
FROM Customers
GROUP BY rating;
HAVING COUNT (*) = 3;
SQL . Ratingcount ? , ! SQL, .
, , , . , , SQL .
, Ratingcount , GROUP BY, .
. , , , , , , .
, , :
CREATE VIEW Totalforday
AS SELECT odate, COUNT(DISTINCT cnum), COUNT(DISTINCT snum),
COUNT(onum), AVG(amt), SUM(amt)
FROM Orders
GROUP BY odate;
:
SELECT *
FROM Totalforday;
, SQL , , , .
, .