在MySQL的同一列中选择两个不同的值

Question

QUERY

SELECT *
FROM `products`
WHERE (
`category` = 'a'
AND `category` = 'b'
)

MySQL

products
---
id      sku     category
-------------------------
1       34343   a
2       32523   d
3       23234   b
4       23433   b
5       23442   c

I want to return A and B

Answer 1

SELECT *
FROM `products`
WHERE (
`category` = 'a'
OR `category` = 'b'
)

OR

SELECT *
FROM `products`
WHERE
`category` IN ('a', 'b')

You can use IN clause to replace many OR conditions. IN simply checks whether a value is within a set of values.

Answer 2

You have to use the OR operator because with AND you select where category is A and B but you have to select where category are A or B

SELECT *
FROM `products`
WHERE (
`category` = 'a' OR `category` = 'b'
)

Answer 3

SELECT *
FROM `products`
WHERE `category` in('a','b')

Answer 4

SELECT * FROM products WHERE category （'a'，'b'）

Answer 5

you can do like this:

SELECT c1 FROM table WHERE c2 IN (1,2,3,4) GROUP BY c1 HAVING COUNT(c2)=4;