我想向表中插入数据,但只插入数据库中不存在的数据。
这是我的代码:
ALTER PROCEDURE [dbo].[EmailsRecebidosInsert]
(@_DE nvarchar(50),
@_ASSUNTO nvarchar(50),
@_DATA nvarchar(30) )
AS
BEGIN
INSERT INTO EmailsRecebidos (De, Assunto, Data)
VALUES (@_DE, @_ASSUNTO, @_DATA)
WHERE NOT EXISTS ( SELECT * FROM EmailsRecebidos
WHERE De = @_DE
AND Assunto = @_ASSUNTO
AND Data = @_DATA);
END
错误是:
Msg 156,级别15,状态1,程序EmailsRecebidosInsert,第11行
关键字WHERE附近的语法不正确。
INSERT命令没有WHERE子句——你必须这样写:
ALTER PROCEDURE [dbo].[EmailsRecebidosInsert]
(@_DE nvarchar(50),
@_ASSUNTO nvarchar(50),
@_DATA nvarchar(30) )
AS
BEGIN
IF NOT EXISTS (SELECT * FROM EmailsRecebidos
WHERE De = @_DE
AND Assunto = @_ASSUNTO
AND Data = @_DATA)
BEGIN
INSERT INTO EmailsRecebidos (De, Assunto, Data)
VALUES (@_DE, @_ASSUNTO, @_DATA)
END
END
我会使用合并:
create PROCEDURE [dbo].[EmailsRecebidosInsert]
(@_DE nvarchar(50),
@_ASSUNTO nvarchar(50),
@_DATA nvarchar(30) )
AS
BEGIN
with data as (select @_DE as de, @_ASSUNTO as assunto, @_DATA as data)
merge EmailsRecebidos t
using data s
on s.de = t.de
and s.assunte = t.assunto
and s.data = t.data
when not matched by target
then insert (de, assunto, data) values (s.de, s.assunto, s.data);
END
不同的SQL,相同的原理。仅当where not exists中的子句失败时才插入
INSERT INTO FX_USDJPY
(PriceDate,
PriceOpen,
PriceLow,
PriceHigh,
PriceClose,
TradingVolume,
TimeFrame)
SELECT '2014-12-26 22:00',
120.369000000000,
118.864000000000,
120.742000000000,
120.494000000000,
86513,
'W'
WHERE NOT EXISTS
(SELECT 1
FROM FX_USDJPY
WHERE PriceDate = '2014-12-26 22:00'
AND TimeFrame = 'W')
根据你的SQL Server版本(2012?),除了IF EXISTS,你还可以像这样使用MERGE:
ALTER PROCEDURE [dbo].[EmailsRecebidosInsert]
( @_DE nvarchar(50)
, @_ASSUNTO nvarchar(50)
, @_DATA nvarchar(30))
AS BEGIN
MERGE [dbo].[EmailsRecebidos] [Target]
USING (VALUES (@_DE, @_ASSUNTO, @_DATA)) [Source]([De], [Assunto], [Data])
ON [Target].[De] = [Source].[De] AND [Target].[Assunto] = [Source].[Assunto] AND [Target].[Data] = [Source].[Data]
WHEN NOT MATCHED THEN
INSERT ([De], [Assunto], [Data])
VALUES ([Source].[De], [Source].[Assunto], [Source].[Data]);
END
INSERT命令没有WHERE子句——你必须这样写:
ALTER PROCEDURE [dbo].[EmailsRecebidosInsert]
(@_DE nvarchar(50),
@_ASSUNTO nvarchar(50),
@_DATA nvarchar(30) )
AS
BEGIN
IF NOT EXISTS (SELECT * FROM EmailsRecebidos
WHERE De = @_DE
AND Assunto = @_ASSUNTO
AND Data = @_DATA)
BEGIN
INSERT INTO EmailsRecebidos (De, Assunto, Data)
VALUES (@_DE, @_ASSUNTO, @_DATA)
END
END