之間和加入單個查詢

Question

gradeid | startrange | endrange 
---------------------- 
A | 50000 | 1000000 
B | 25000 | 49999 
C | 10000 | 24999 

Employee 
id | salary 
----------- 
1 | 23000 
2 | 20000 
3 | 100000 

我想在單個查詢中獲得所有員工的成績。因爲沒有共同的字段，我可以用兩個子查詢來做到這一點。

select id from employee where salary 
    between (select startrange from grade where gradeid='A') 
and (select endrange from grade where gradeid='A') 

還有其他更好的SQL查詢嗎？

Answer 1

您可以使用JOIN：

CREATE TABLE #grades(gradeid VARCHAR(100), startrange INT, endrange INT); 

INSERT INTO #grades 
VALUES ('A', 50000, 1000000),('B', 25000, 49999),('C', 10000, 24999); 

CREATE TABLE #Employee(id INT, salary INT); 

INSERT INTO #Employee VALUES(1, 23000),(2, 20000),(3, 100000); 

SELECT e.* 
FROM #Employee e 
JOIN #grades g 
    ON e.salary BETWEEN startrange AND endrange 
WHERE g.gradeid = 'A'; 

LiveDemo