Question

我在这个数据库里面有一个名为accounts和account的数据库，另外我在这个数据库里面得到了一个名为players和player的数据库。

如何在一个查询中获取这两个表的行数？

我试过这个：

SELECT
    SUM(`account`.`account`.`id`) AS 'accounts',
    SUM(`player`.`player`) AS 'players';

但它不起作用。

Answer 1

对两个select语句执行简单的UNION操作：

SELECT COUNT(*), 'Accounts' FROM Accounts.Account
UNION
SELECT COUNT(*), 'Players' FROM Players.Player

并且您必须使用数据库名称限定每个表，因为它们位于不同的数据库中。

Answer 2

如果您需要精确的行数（而不是总和），请执行以下操作：

select
(select count(*) from accounts.account) as count1,
(select count(*) from players.player) as count2

或

select count(*) as `count`,"account" as `table` from accounts.account
union all
select count(*) as `count`,"player" as `table` from players.player

Answer 3

尝试：

SELECT
   COUNT(`account`.`id`) AS 'accounts',
   COUNT(`player`.`player`) AS 'players'
FROM
   `account`,
   `player`

Answer 4

SELECT COUNT(*) 
FROM (
    SELECT Id 
    FROM accounts.account 
    UNION ALL 
    SELECT player 
    FROM players.player ) AS BothTables

Answer 5

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如何在一个查询中获取2个不同表（和数据库）的行数？

5 个答案: