如何检查两个不同表中两列数据的存在?的MySQL [英] How to check the existence of two columns' data in two different tables ? MySQL

问题描述

我在两个不同的数据库中有两个不同的表..

I have two different tables in two different databases ..

我要做的是检查另一列中是否存在两列的数据..如果确实存在，请对其进行计数，最后我希望在另一张表中具有匹配项的记录数.

what I want to do is to check if the data of two columns exist in the other table .. if it does exist count it and at the final I want the number of records that have matching in the other table.

示例:

表_1

column_1值=狗"

column_1 value = "dog"

column_2值=苹果"

column_2 value = "apple"

table_2

column_1值=狗"

column_1 value = "dog"

column_2值=橙色"

column_2 value = "orange"

所以这里第一列的值在两个表中都存在，但是第二列是不同的，所以我不想对其进行计数..我想对两个值在同一记录中的位置进行计数.

so here the first column values exist in both table but the second column is different so I don't want to count it .. I want to count where both values exist in the same record .

ps:column_1和column_2都不是主键

ps: Both column_1 and column_2 aren't primary key

是否有使用MySQL的解决方案?因为我用Java解决了这个问题，但要花很长时间才能获得500万条记录.

is there a solution for it using MySQL ? because I used java to solve this but take a long time for 5 million records .

推荐答案

在两个表上都执行INNER JOIN:

SELECT COUNT(*)
FROM table_1 t1
INNER JOIN table_2 t2
    ON t1.column_1 = t2.column_1
    AND t1.column_2 = t2.column_2

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