Question

SQL如何统计多表总记录数

有5张表 ，如何统计总记录数

Answer 1

你是指5张表的总记录还是相关的记录？
SELECT SUN(C) FROM (
SEELCT COUNT(*) C FROM TABLE1
UNION ALL
SEELCT COUNT(*) C FROM TABLE2
UNION ALL
SEELCT COUNT(*) C FROM TABLE3
UNION ALL
SEELCT COUNT(*) C FROM TABLE4
UNION ALL
SEELCT COUNT(*) C FROM TABLE5
);
或者：
SELECT COUNT(*) FROM TABLE1 A
INNER JOIN TABLE2 B ON A.ID=B.ID
INNER JOIN TABLE3 C ON C.ID=B.ID
INNER JOIN TABLE4 D ON D.ID=C.ID
INNER JOIN TABLE5 E ON E.ID=D.ID

追问

提示错误
Every derived table must have its own alias
SELECT SUN(C) FROM (select count(id) C from news UNION All select count(id) C from bbs)

追答

ORACLE 码？

追问

MYSQL

追答

MY SQL我没发测试。你看，把表加个别名试下好吧

Answer 2

SELECT COUNT(COL) FROM
(
SELECT COL1 AS COL FROM TB1
)
UNION ALL
(
SELECT COL2 AS COL FROM TB2
)
WITH UR;
COL1和COL2最好是各自表的主键，你要查多个表的话在后面继续UNION ALL就行了，注意COL的名字要一样

Answer 3

有2个方法：
1、select *,(select count(u_id) from h_travel_line where u_id = a.u_id) 已线路数
from h_travel a
2、SELECT c.ttt AS 已线路数, h_travel.*
FROM h_travel INNER JOIN
(SELECT COUNT(*) AS ttt, u_id
FROM h_travel_line
GROUP BY STID) c
ON h_travel.u_id =c.u_id

Answer 4

这样对吗：

SELECT SUm(C) FROM
(
select count(id) C from news
UNION All
select count(id) C from bbs
) a

追问

FUNCTION data.SUN does not exist

追答

真晕，你写错了， 应该是sum，而不是sun

我给你改掉了，你也没有看见 ？

追问

这次不提示错误了，执行的时候是用query还是其他的呢？

追答

mysql接触的不多

而且你用的是什么工具啊 ？

追问

PHP

追答

呵呵，更加不懂了。

Answer 5

问题描述的不够清晰！如果他们有关系的话，你把他们连接起来然后count就可以了啊