Mysql 长时间运行的查询问题

我正在尝试用一个脚本来解决一些问题，我没有编写这个脚本，因为该站点似乎很快就填满了mysql

/tmp

目录

我检查了

慢速查询日志

，它有很多这样的查询

SELECT
    COUNT(*) AS `total`
FROM
    (
        SELECT
                *
        FROM
            `Advertising_Business_and_Retail`
        WHERE
            MATCH (`wm`, `locn`, `gns`) AGAINST('outdoor apparel company')
    UNION
        SELECT
                *
        FROM
            `Chemical` WHERE MATCH (`wm`, `locn`, `gns`) AGAINST('outdoor apparel company')
    UNION
        SELECT
                *
        FROM `Clothing` WHERE MATCH (`wm`, `locn`, `gns`) AGAINST('outdoor apparel company')
    )
AS t;

除了我认为总共有45个工会（每个类别表1个）之外，这些表并不庞大，但是广告、商业和零售表本身就有大约450k个

我手动运行了这个查询，大约花了2.5分钟

我猜这就是为什么/tmp目录填充得这么快的原因吧

---

关于如何解决此问题的任何提示？

如果您确定所选行中没有重复的行，请尝试将

联合

替换为

联合所有

此外，您还可以使用简单的添加来替换

UINON-ALL

：

select (
  (select count(1) from `Advertising_Business_and_Retail` WHERE MATCH (`wm`, `locn`, `gns`) AGAINST('outdoor apparel company'))
+ (select count(1) from `Chemical` WHERE MATCH (`wm`, `locn`, `gns`) AGAINST('outdoor apparel company'))
+ (select count(1) from `Clothing` WHERE MATCH (`wm`, `locn`, `gns`) AGAINST('outdoor apparel company'))
) as total

这快一点吗

SELECT
    SUM(`count`) AS `total`
FROM
    (
        SELECT
               COUNT(*) AS `count`
        FROM
            `Advertising_Business_and_Retail`
        WHERE
            MATCH (`wm`, `locn`, `gns`) AGAINST('outdoor apparel company')
    UNION
        SELECT
               COUNT(*) AS `count`
        FROM
            `Chemical` WHERE MATCH (`wm`, `locn`, `gns`) AGAINST('outdoor apparel company')
    UNION
        SELECT
                COUNT(*) AS `count`
        FROM `Clothing` WHERE MATCH (`wm`, `locn`, `gns`) AGAINST('outdoor apparel company')
    )
AS t;