ham_tong (bieuthuc)
FROM bang
[WHERE dieukien]
GROUP BY bieuthuc1, bieuthuc2, … bieuthuc_n
HAVING dieukie
n_having; ham_tong
Can be functions like SUM, COUNT, MIN, MAX or AVG.
bieuthuc1, bieuthuc2, . bieuthuc_n
The expression is not within the total function and must be in the GROUP BY clause.
WHERE dieukien
Option. The conditions that the record must meet to be selected.
HAVING dieukien_having
This is an additional condition that applies only to the total result to limit the groups of returned rows. Only groups whose conditions are evaluated are TRUE in the result set.
For example - use the SUM function
SELECT bophan, SUM(soluong) AS 'Tong so luong'
FROM sanpham
GROUP BY bophan
HAVING SUM (soluong) > 1
00;
The example of the above HAVING clause uses the SUM function to return the department name and the total quantity (in the relevant department). The HAVING clause will filter the results so that only parts with a number greater than 100 are returned.
For example - use the COUNT function
SELECT thanhpho, COUNT (*) AS 'So nhanvien'
FROM nhanvien
WHERE bang = 'California'
GROUP BY thanhpho
HAVING COUN
T (*)> 20;
This example returns to the city and the number of employees (in that city) currently in California. The HAVING clause will filter to return only cities with more than 20 employees.
For example - use the MIN function
SELECTbophan, MIN (luong) AS 'Luong thap nhat'
FROM nhanvien
GROUP BY bophan
HAVING MIN
(luong)> = 50000;
In this example, the returned result is the name of each department and the minimum wage in each department. The HAVING clause will only return parts with a minimum wage greater than or equal to $ 50,000.
For example - use the MAX function
SELECT ho, MAX (luong) AS 'Luong cao nhat'
FROM nhanvien
GROUP BY bophan
HAVING MA
X (luong)> 34000;
In this final example, the result is the employee's last name and the maximum salary for that family's value. The HAVING clause limits only the values they have the maximum salary greater than $ 34,000.
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