php - 如何从具有两个条件的表中选择数据

Question

我需要从具有联合的两个条件的表中选择数据，或者如果有表的话

    name       special

    Deepak         s
    mukesh         v
    dinesh         s
    girgesh        v
    Deepak         s
    mukesh         v
    dinesh         s
    girgesh        v
    Deepak         s
    mukesh         v
    dinesh         s
    girgesh        v

查询获取数据...

SELECT NAME FROM  student WHERE special = "s" LIMIT 2
UNION 
SELECT NAME FROM student WHERE special = "v"  LIMIT 2

但它只给出合并前的第一个条件...如何从一张表中获取两个不同条件的数据

Answer 1

根据 MySQL's documentation on UNION :

To apply ORDER BY or LIMIT to an individual SELECT, place the clause inside the parentheses that enclose the SELECT

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所以你想使用:

(SELECT NAME FROM  student WHERE special = "s" LIMIT 2)
UNION 
(SELECT NAME FROM student WHERE special = "v"  LIMIT 2)