比如在格式为DBF的表1中有如下数据:
水果店商店编号 水果种类 销售数量
1 苹果 1250
1 香蕉 1326
1 西瓜 236
1 西红柿 2365
1 草莓 3695
2 苹果 2250
2 香蕉 2326
2 西瓜 1364
2 西红柿 1365
2 草莓 2695
.
.
.问题:
如何通过SQL语句,显示出每家水果店的前几行记录(比如显示前3行记录),应该如何实现呢?
实现后的效果如下:
水果店商店编号 水果种类 销售数量
1 苹果 1250
1 香蕉 1326
1 西瓜 236
2 苹果 2250
2 香蕉 2326
2 西瓜 1364
水果店商店编号 水果种类 销售数量
1 苹果 1250
1 香蕉 1326
1 西瓜 236
1 西红柿 2365
1 草莓 3695
2 苹果 2250
2 香蕉 2326
2 西瓜 1364
2 西红柿 1365
2 草莓 2695
.
.
.问题:
如何通过SQL语句,显示出每家水果店的前几行记录(比如显示前3行记录),应该如何实现呢?
实现后的效果如下:
水果店商店编号 水果种类 销售数量
1 苹果 1250
1 香蕉 1326
1 西瓜 236
2 苹果 2250
2 香蕉 2326
2 西瓜 1364
--go
--CREATE TABLE test_fruit
--(
-- id INT,
-- [name] NVARCHAR(22),
-- [price] DECIMAL(18,2)
--)--INSERT INTO test_fruit
--SELECT 1 AS 'id' ,'苹果' AS 'name',1250 AS 'price' UNION ALL
--SELECT 1 AS 'id' ,'香蕉' AS 'name',1326 AS 'price' UNION ALL
--SELECT 1 AS 'id' ,'西瓜' AS 'name',236 AS 'price' UNION ALL
--SELECT 1 AS 'id' ,'西红柿' AS 'name',2365 AS 'price' UNION ALL
--SELECT 1 AS 'id' ,'草莓' AS 'name',3695 AS 'price' UNION ALL
--SELECT 2 AS 'id' ,'苹果' AS 'name',2250 AS 'price' UNION ALL
--SELECT 2 AS 'id' ,'香蕉' AS 'name',2326 AS 'price' UNION ALL
--SELECT 2 AS 'id' ,'西瓜' AS 'name',1364 AS 'price' UNION ALL
--SELECT 2 AS 'id' ,'西红柿' AS 'name',1365 AS 'price' UNION ALL
--SELECT 2 AS 'id' ,'草莓' AS 'name',2695
GO
SELECT *
FROM test_fruit a
WHERE name IN ( SELECT TOP 3
name
FROM test_fruit
WHERE id = a.id
ORDER BY id )
id name price
----------- ---------------------- ---------------------------------------
1 苹果 1250.00
1 香蕉 1326.00
1 西瓜 236.00
2 苹果 2250.00
2 香蕉 2326.00
2 西瓜 1364.00(6 行受影响)
加入自增字段ID
ALTER table ttt ADD id i AUTOINCSELECT * FROM tth a WHERE 3>(select COUNT(*) FROM tth WHERE a.水果店编号=水果店编号 AND a.id>id)否则在DBF中加入唯一标识的字段
-- Author: liangCK 小梁
-- Title : 查每个分组前N条记录
-- Date : 2008-11-13 17:19:23
-----------------------------------> 生成测试数据: #T
IF OBJECT_ID('tempdb.dbo.#T') IS NOT NULL DROP TABLE #T
CREATE TABLE #T (ID VARCHAR(3),GID INT,Author VARCHAR(29),Title VARCHAR(39),Date DATETIME)
INSERT INTO #T
SELECT '001',1,'邹建','深入浅出SQLServer2005开发管理与应用实例','2008-05-10' UNION ALL
SELECT '002',1,'胡百敬','SQLServer2005性能调校','2008-03-22' UNION ALL
SELECT '003',1,'格罗夫Groff.J.R.','SQL完全手册','2009-07-01' UNION ALL
SELECT '004',1,'KalenDelaney','SQLServer2005技术内幕存储引擎','2008-08-01' UNION ALL
SELECT '005',2,'Alex.Kriegel.Boris.M.Trukhnov','SQL宝典','2007-10-05' UNION ALL
SELECT '006',2,'飞思科技产品研发中心','SQLServer2000高级管理与开发','2007-09-10' UNION ALL
SELECT '007',2,'胡百敬','SQLServer2005数据库开发详解','2008-06-15' UNION ALL
SELECT '008',3,'陈浩奎','SQLServer2000存储过程与XML编程','2005-09-01' UNION ALL
SELECT '009',3,'赵松涛','SQLServer2005系统管理实录','2008-10-01' UNION ALL
SELECT '010',3,'黄占涛','SQL技术手册','2006-01-01'--SQL查询如下:--按GID分组,查每个分组中Date最新的前2条记录
--1.字段ID唯一时:
SELECT * FROM #T AS T WHERE ID IN(SELECT TOP 2 ID FROM #T WHERE GID=T.GID ORDER BY Date DESC)--2.如果ID不唯一时:
SELECT * FROM #T AS T WHERE 2>(SELECT COUNT(*) FROM #T WHERE GID=T.GID AND Date>T.Date)--SQL Server 2005 使用新方法--3.使用ROW_NUMBER()进行排位分组
SELECT ID,GID,Author,Title,Date
FROM
(
SELECT rid=ROW_NUMBER() OVER(PARTITION BY GID ORDER BY Date DESC),*
FROM #T
) AS T
WHERE rid<=2--4.使用APPLY
SELECT DISTINCT b.*
FROM #T AS a
CROSS APPLY
(
SELECT TOP(2) * FROM #T WHERE a.GID=GID ORDER BY Date DESC
) AS b
--结果
/*ID GID Author Title Date
---- ----------- ----------------------------- --------------------------------------- -----------------------
003 1 格罗夫Groff.J.R. SQL完全手册 2009-07-01 00:00:00.000
004 1 KalenDelaney SQLServer2005技术内幕存储引擎 2008-08-01 00:00:00.000
005 2 Alex.Kriegel.Boris.M.Trukhnov SQL宝典 2007-10-05 00:00:00.000
007 2 胡百敬 SQLServer2005数据库开发详解 2008-06-15 00:00:00.000
009 3 赵松涛 SQLServer2005系统管理实录 2008-10-01 00:00:00.000
010 3 黄占涛 SQL技术手册 2006-01-01 00:00:00.000(6 行受影响)
*/--得到每组前几条数据
--假設每組Col1中, Col3不會重復--建立測試環境
Create Table TEST
(Col1 Varchar(10),
Col2 Varchar(10),
Col3 Int)
--插入數據
Insert TEST Select 'BD1V','Label', 4
Union All Select 'BD1V', 'BATT', 2
Union All Select 'BD1V', 'ODD', 3
Union All Select 'BD1V', 'HDD', 5
Union All Select 'BD1V', 'LCD', 1
Union All Select 'BD1W','HDD', 3
Union All Select 'BD1W','RAM', 8
Union All Select 'BD1W','TP CABLE', 5
Union All Select 'BD1W','LCD', 6
Union All Select 'BD1W','Label', 2
Union All Select 'BL3', 'LCD CABLE', 7
Union All Select 'BL3', 'LABEL', 6
Union All Select 'BL3', 'LCD', 5
Union All Select 'BL3', 'RAM', 1
Union All Select 'BL3D', 'Label', 4
GO
--測試
--方法一:
Select Col1, Col2, Col3 From TEST A
Where (Select Count(*) From TEST Where Col1 = A.Col1 And Col3 > A.Col3) < 3
Order By Col1, Col3 Desc
--方法二:
Select Col1, Col2, Col3 From TEST A
Where Exists (Select Count(*) From TEST Where Col1 = A.Col1 And Col3 > A.Col3 Having Count(*) < 3)
Order By Col1, Col3 Desc
--方法三:
Select Col1, Col2, Col3 From TEST A
Where Col3 In (Select TOP 3 Col3 From TEST Where Col1 = A.Col1 Order By Col3 Desc)
Order By Col1, Col3 Desc
GO
--刪除測試環境
Drop Table TEST
--結果
/*
Col1 Col2 Col3
BD1V HDD 5
BD1V Label 4
BD1V ODD 3
BD1W RAM 8
BD1W LCD 6
BD1W TP CABLE 5
BL3 LCD CABLE 7
BL3 LABEL 6
BL3 LCD 5
BL3D Label 4
*/
表里没有唯一的值,在不要改变表整体结构的情况下 有办法实现吗?因为表的结构我没有权限改变。我只能通过SQL语句来实现。需要支持ACCESS数据库操作的SQL语句
麻烦了