㈠ 如何用sql查詢出最新的記錄變化詳見以下描述,謝謝!
oracle的寫法:
SELECT
*
(
SELECT
c.* ,
row_number() over (partition by c.timech order by a.timech desc) rn
FROM
(
SELECT
Xh,
xm,
zt,
timech
FROM
Student
UNION ALL
SELECT
b.Xh,
b.xm,
a.ztchange,
a.timech
FROM
Change a,
Student b
WHERE
a.xh = b.xh
and c.timech <= '2011.1.20'
)
c
)
WHERE
rn = 1
㈡ sql如何查詢每個用戶最新的一條信息
你的from和to是關鍵字,這里用id1和id2表示。
創建表及插入數據(在你基礎上多加了一條數據):
createtabletest
(id1int,
id2int,
timedatetime)
insertintotestvalues(1,2,'2017-03-1615:18:00')
insertintotestvalues(2,1,'2017-03-1615:21:00')
insertintotestvalues(1,2,'2017-03-1616:00:00')
執行:
selectt2.*from
(selectcasewhenid1>id2thenid1elseid2endid1,
casewhenid1>id2thenid2elseid1endid2,
max(time)>id2thenid1elseid2end,casewhenid1>id2thenid2elseid1end)t1,
testt2
where(t1.id1=t2.id1andt1.id2=t2.id2andt1.time=t2.time)or(t1.id1=t2.id2andt1.id2=t2.id1andt1.time=t2.time)
結果:
㈢ 怎樣在sql表查詢最新10條記錄
select*from
(selecttop10*from表名orderbydate1)table1orderbydate1desc
以上這段sql語句是查詢表中最新的10條記錄
第一步是要按照「日期」降序排列
第二步取前10條
㈣ 用SQL語句怎樣從表裡查詢出最新的8條信息
select top 8 * from gonggao order by gonggaoid desc
㈤ 首頁新聞列表中,按時間顯示最新插入資料庫的5條新聞信息,SQL查詢語句應該怎麼寫
select top 5 N_ID,N_TITLE,N_TIME from 表的名字 Order by N_TIME desc
㈥ sql查詢最近一天更新狀況
select *
from table
where trunc(收發簡訊時間) = trunc(sysdate)
一個月/年 就截取日期 即可
㈦ MYSQL查詢一張表如何查詢出最新信息
假設表名是D, 正確答案如下:
select t2.eid, t2.ename, t2.yearmonth
from D t2
join
(
select t1.eid, max(t1.yearmonth) as yearmonth
from D t1
group by t1.eid
) t3
on t2.eid = t3.eid and t2.yearmonth = t3.yearmonth
運行通過後請採納,謝謝!
㈧ sql 查資料庫中時間最新的一條記錄
select *,max(create_time) from a
where create_time<="2017-03-29 19:30:36"
group by user_id
這句可以理解為將結果集根據user_id分組,每組取time最大一條記錄。這樣就很好的實現了批量查詢最近記錄,並且僅僅需要遍歷一次表,即使在數據量巨大的情況下也可以在很短的時間查出結果。
(8)sql最近新消息擴展閱讀:
SQL數據查詢語句
1、語句語法簡單歸納為:
SELECTselect_list[INTOnew_table_name] [FROMtable_source]
[WHEREsearch_condition] [GROUP BYgroup_by_expression]
[HAVINGsearch_condition] [ORDER BYorder_expression[ASC | DESC]]
2、WITH子句用於指定臨時命名的公用表達式,在單條語句(SELECT、INSERT、UPDATE、DELETE)的語句執行范圍內定義。
3、LIKE關鍵字
用於模糊查詢,通配符有%、_、[ ]、[^]
%:後面可以跟零個或多個字元
_:匹配任意單個字元
[ ]:查詢一定范圍內的單個字元,包括兩端數據
[^]:表示不在一定范圍內的單個字元,包括兩端數據
㈨ sql取各個欄目最新的幾條信息
--查每個分組前N條記錄
--> 生成測試數據: #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,'鄒建','深入淺出SQLServer2005開發管理與應用實例','2008-05-10' UNION ALL
SELECT '002',1,'胡百敬','SQLServer2005性能調校','2008-03-22' UNION ALL
SELECT '003',1,'格羅夫Groff.J.R.','SQL完全手冊','2009-07-01' UNION ALL
SELECT '004',1,'KalenDelaney','SQLServer2005技術內幕存儲引擎','2008-08-01' UNION ALL
SELECT '005',2,'Alex.Kriegel.Boris.M.Trukhnov','SQL寶典','2007-10-05' UNION ALL
SELECT '006',2,'飛思科技產品研發中心','SQLServer2000高級管理與開發','2007-09-10' UNION ALL
SELECT '007',2,'胡百敬','SQLServer2005資料庫開發詳解','2008-06-15' UNION ALL
SELECT '008',3,'陳浩奎','SQLServer2000存儲過程與XML編程','2005-09-01' UNION ALL
SELECT '009',3,'趙松濤','SQLServer2005系統管理實錄','2008-10-01' UNION ALL
SELECT '010',3,'黃占濤','SQL技術手冊','2006-01-01'
--SQL查詢如下:
--按GID分組,查每個分組中Date最新的前2條記錄
--1.欄位ID唯一時:
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不唯一時:
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()進行排位分組
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
--結果
/*
ID GID Author Title Date
---- ----------- ----------------------------- --------------------------------------- -----------------------
003 1 格羅夫Groff.J.R. SQL完全手冊 2009-07-01 00:00:00.000
004 1 KalenDelaney SQLServer2005技術內幕存儲引擎 2008-08-01 00:00:00.000
005 2 Alex.Kriegel.Boris.M.Trukhnov SQL寶典 2007-10-05 00:00:00.000
007 2 胡百敬 SQLServer2005資料庫開發詳解 2008-06-15 00:00:00.000
009 3 趙松濤 SQLServer2005系統管理實錄 2008-10-01 00:00:00.000
010 3 黃占濤 SQL技術手冊 2006-01-01 00:00:00.000
(6 行受影響)
*/
--得到每組前幾條數據
--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
*/
㈩ 查詢指定用戶ID發布的的最新信息SQL怎麼寫
假設你有一張表存儲了最新發布信息,當中存在發布時間列,則你可以這樣寫:
select * from 發布信息表 p
join
(
select 用戶ID,max(發布時間) as '最新發布時間'from 發布信息表
where 用戶ID='××'
--如果你是多個用戶查詢,改成把「=」改成in,然後在 where後面加上group by 用戶ID
) s
on p.用戶ID=s.用戶ID and p.發布時間=s.最新發布時間