单个查询SQL中的多个数据范围

Question

I have a student table now I want to write a query that return a single student in a specified ranges. For example if I provide two ranges (30 to 40) and (40 to 60), query should return me 2 students one which is in the range 30 to 40 and one in the range 40 to 60. How can I write a single query?

Answer 1

Use two selects with different ranges in where statement combined by UNION

Example:

(SELECT * FROM students WHERE ranges BETWEEN 30 AND 40 LIMIT 1)
UNION
(SELECT * FROM students WHERE ranges BETWEEN 40 AND 60 LIMIT 1)

Answer 2

You can use OR condition:

(range between 30 and 40) OR (range between 40 and 60) .

and CASE :

CASE WHEN range between 30 and 40 then 'X' else 'Y' as CLASS

and then you can use GROUP BY to select 1 record for class so:

SELECT MAX(STUDENT_ID), CASE WHEN range between 30 and 40 then 'X' else 'Y' as CLASS
FROM MY_TABLE
GROUP BY CLASS