countsql多表

『壹』 SQL如何統計多表總記錄數

有2個方法：
1、select
*,(select
count(u_id)
from
h_travel_line
where
u_id
=
a.u_id)
已線路數
from
h_travel
a
2、SELECT
c.ttt
AS
已線路數,
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

『貳』 SQL如何統計多表總記錄數

你是指5張表的總記錄還是相關的記錄？
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

『叄』 如何統計SQL語句查詢出來的條數

i=SELECT count(1) FROM TABLE

語句返回值即為查詢出來的條數.

示例如圖所示:

擴展:

COUNT() 函數返回匹配指定條件的行數。

語法

(1). SQL COUNT(column_name) 語法

COUNT(column_name) 函數返回指定列的值敗敗的數目（NULL 不計入）：

SELECT COUNT(column_name) FROM table_nameSQL

(2). COUNT(*) 語氏迅法

COUNT(*) 函數返回殲枯此表中的記錄數：

SELECT COUNT(*) FROM table_nameSQL

(3). COUNT(DISTINCT column_name) 語法

COUNT(DISTINCT column_name) 函數返回指定列的不同值的數目：

SELECT COUNT(DISTINCT column_name) FROM table_name