目錄
判斷語句
賦值
IF(@v_count <> 0)
BEGIN
SELECT @v_team_id=team_id FROM TABLE T WHERE T.column=1;
END
ELSE
BEGIN
SET@v_team_name='無';
END
多行轉一行
https://www.cnblogs.com/CreateMyself/p/9058380.html
SELECT STUFF((SELECT '/' + T.column FROM Table T FOR XML PATH('')), 1, 1, '');
oracle:listagg
CASE WHEN ELSE END
SELECT CASE column WHEN 'a' THEN 'b' ELSE 'c' END from Table
oracle
select decode(column,'a','b','c') WORK_CERT_TYPE_name from Table
判斷某個值是否為null，否則替換
ISNULL(oldTeamID, 0)
oracle
nvl(oldTeamID,0)
執行存儲過程,getdate() 直接做參數會報錯
SET @startDate = GETDATE();
execute hr.Insert @pUserId, -1, @startDate, null
update 表別名
UPDATE T SET T.TID=1,T.TNAME='Name',T.TClass=1 FROM [TABLE] T WHERE T.ID=10
oracle
UPDATE TABLE T SET T.TID=1,T.TNAME='Name',T.TClass=1 WHERE T.ID=10
創建序列
CREATE SEQUENCE event_seq
MINVALUE 1
MAXVALUE 999999999999999999
START WITH 1
INCREMENT BY 1
CACHE 20;
--使用時
GO
SELECT next value for event_seq
如果設置列默認值為序列的話填入 next value for event_seq
查看數據庫最近執行的語句
https://www.cnblogs.com/chenjianxiang/p/7833588.html
SELECT TOP 1000
ST.text AS '執行的SQL語句',
QS.execution_count AS '執行次數',
QS.total_elapsed_time AS '耗時',
QS.total_logical_reads AS '邏輯讀取次數',
QS.total_logical_writes AS '邏輯寫入次數',
QS.total_physical_reads AS '物理讀取次數',
QS.creation_time AS '執行時間' ,
QS.*
FROM sys.dm_exec_query_stats QS
CROSS APPLY
sys.dm_exec_sql_text(QS.sql_handle) ST
WHERE QS.creation_time BETWEEN '2019-07-24 00:00:00' AND '2019-07-25 11:00:00'
ORDER BY QS.creation_time desc;
連接符
+
oracle
||
數字 轉 字符串 表達式 和去除左右空格
SELECT convert(varchar(10),1234)
SELECT CAST(12 AS varchar(10))
SELECT LTRIM(RTRIM(CAST(user_id AS varchar(20))))
oracle
SELECT to_char(1) FROM dual
trim(to_char(user_id))
分割字符串為表格
ALTER FUNCTION dbo.splitl (
@String VARCHAR(MAX),
@Delimiter VARCHAR(MAX)
) RETURNS @temptable TABLE (items VARCHAR(MAX)) AS
BEGIN
DECLARE @idx INT=1
DECLARE @slice VARCHAR(MAX)
IF LEN(@String) < 1 OR LEN(ISNULL(@String,'')) = 0
RETURN
WHILE @idx != 0
BEGIN
SET @idx = CHARINDEX(@Delimiter,@String)
IF @idx != 0
SET @slice = LEFT(@String,@idx - 1)
ELSE
SET @slice = @String
IF LEN(@slice) > 0
INSERT INTO @temptable(items) VALUES(@slice)
SET @String = RIGHT (@String, LEN(@String) - @idx)
IF LEN(@String) = 0
BREAK
END
RETURN
END
SELECT * FROM dbo.splitl('a#b#c#d','#')
來源： https://my.oschina.net/cwalet/blog/267386
oracle
SELECT split(a,b,c#,d, ',') FROM TABLE WHERE column = 1
創建臨時表
創建臨時表
方法一：
create table #臨時表名(字段1 約束條件,
字段2 約束條件,
.....)
方法二：
select * into #臨時表名 from 你的表;
select * into ##臨時表名 from 你的表;
注：以上的#代表局部臨時表，##代表全局臨時表
函數返回 table
ALTER FUNCTION [dbo].[returnTable]
(
)
RETURNS @Tables TABLE(one int,two VARCHAR(20),three date ,four date)
AS
BEGIN
INSERT @Tables SELECT * FROM student
RETURN
END
SET NOCOUNT { ON | OFF }
SET NOCOUNT ON
每次我們在使用查詢分析器調試SQL語句的時候，通常會看到一些信息，提醒我們當前有多少個行受到了影響，這是些什么信息？在我們調用的時候這些信息有用嗎？是否可以關閉呢？
答案是這些信息在我們的客戶端的應用程序中是沒有用的，這些信息是存儲過程中的每個語句的DONE_IN_PROC 信息。
我們可以利用SET NOCOUNT 來控制這些信息，以達到提高程序性能的目的。
查詢表結構信息
https://blog.csdn.net/wangxw1803/article/details/90749909
SELECT (case when a.colorder=1 then d.name else null end) 表名,
a.colorder 字段序號,a.name 字段名,
(case when COLUMNPROPERTY( a.id,a.name,'IsIdentity')=1 then '√'else '' end) 標識,
(case when (SELECT count(*) FROM sysobjects
WHERE (name in (SELECT name FROM sysindexes
WHERE (id = a.id) AND (indid in
(SELECT indid FROM sysindexkeys
WHERE (id = a.id) AND (colid in
(SELECT colid FROM syscolumns WHERE (id = a.id) AND (name = a.name)))))))
AND (xtype = 'PK'))>0 then '√' else '' end) 主鍵,b.name 類型,a.length 占用字節數,
COLUMNPROPERTY(a.id,a.name,'PRECISION') as 長度,
isnull(COLUMNPROPERTY(a.id,a.name,'Scale'),0) as 小數位數,(case when a.isnullable=1 then '√'else '' end) 允許空,
isnull(e.text,'') 默認值,isnull(g.[value], ' ') AS [說明]
FROM syscolumns a
left join systypes b on a.xtype=b.xusertype
inner join sysobjects d on a.id=d.id and d.xtype='U' and d.name<>'dtproperties'
left join syscomments e on a.cdefault=e.id
left join sys.extended_properties g on a.id=g.major_id AND a.colid=g.minor_id
left join sys.extended_properties f on d.id=f.class and f.minor_id=0
where b.name is not null
--WHERE d.name='要查詢的表' --如果只查詢指定表,加上此條件
order by a.id,a.colorder
查詢數據庫中的所有數據庫名
SELECT Name FROM Master..SysDatabases ORDER BY Name
查詢所有用戶數據庫的表名
SELECT Name FROM SysObjects Where XType='U' ORDER BY Name