Question

我有以下表格：

CREATE TABLE [dbo].[TurbinaGas5](
    [id] [int] IDENTITY(1,1) NOT NULL,
    [id_central] [int] NULL,
    [presion_agua_alta] [float] NULL,
    [presion_agua_media] [float] NULL,
    [presion_agua_baja] [float] NULL,
    [temperatura_gases_entrando_tg] [float] NULL,
    [fecha] [datetime] NOT NULL,
    [Eficiencia_Camara_Combustion] [float] NULL,
 CONSTRAINT [PK_TurbinaGas5] PRIMARY KEY CLUSTERED 
(
    [id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]



CREATE TABLE [dbo].[TurbinaVapor7](
    [id] [int] IDENTITY(1,1) NOT NULL,
    [id_central] [int] NULL,
    [presion_vapor_alta] [float] NULL,
    [presion_vapor_recalentado_caliente] [float] NULL,
    [consumo_auxiliares] [float] NULL,
    [potencia_neta_medida] [float] NULL,
    [eficiencia_termica_bruta] [float] NULL,
    [fecha] [datetime] NULL,
 CONSTRAINT [PK_TV7] PRIMARY KEY CLUSTERED 
(
    [id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

Database Diagram(sample)

这些表没有关联，尽管它们没有相同的列，但它们的数据使用相同的日期时间戳（Fecha字段）保存。现在，我的问题是我想从两个表中选择一些字段，这些字段是按日期时间过滤的（任何表中的日期，因为它应该是相同的）。

可能你问，为什么不保存同一个表中的所有字段，因为它们在同一时间戳保存？这是因为每个表包含近200个字段，它们属于工厂的不同部分（这个项目是为了一个热电厂。）

两个表只共享字段：id_central作为外键。

我试图像这样构建一个查询：

select tg5.presion_agua_alta, tv7.flujo_vapor_alta from 
TurbinaGas5 tg5 inner join TurbinaVapor7 tv7 on tg5.id_central=tv7.id_central where tg5.fecha between CONVERT(DATETIME,'2017-04-18 01:50:00',102) and CONVERT(DATETIME,'2017-04-19 09:41:00',102)

但是此查询返回数百万行并杀死服务器。谢谢

例如，假设表存储了以下数据：

SET IDENTITY_INSERT [dbo].[TurbinaVapor7] ON
INSERT [dbo].[TurbinaVapor7] ([id], [id_central], [presion_vapor_alta], [presion_vapor_recalentado_caliente], [consumo_auxiliares], [potencia_neta_medida], [eficiencia_termica_bruta], [fecha]) VALUES (11983, 1, 4, 5, 6, 7, 9, CAST(0x0000A75A0128A180 AS DateTime))
INSERT [dbo].[TurbinaVapor7] ([id], [id_central], [presion_vapor_alta], [presion_vapor_recalentado_caliente], [consumo_auxiliares], [potencia_neta_medida], [eficiencia_termica_bruta], [fecha]) VALUES (11985, 1, 9, 10, 11, 12, 13, CAST(0x0000A75A011826C0 AS DateTime))
SET IDENTITY_INSERT [dbo].[TurbinaVapor7] OFF
/****** Object:  Table [dbo].[TurbinaGas5]    Script Date: 04/19/2017 18:29:50 ******/
SET IDENTITY_INSERT [dbo].[TurbinaGas5] ON
INSERT [dbo].[TurbinaGas5] ([id], [id_central], [presion_agua_alta], [presion_agua_media], [presion_agua_baja], [temperatura_gases_entrando_tg], [fecha], [Eficiencia_Camara_Combustion]) VALUES (12024, 1, 1, 2, 3, 4, CAST(0x0000A75A0128A180 AS DateTime), 5)
INSERT [dbo].[TurbinaGas5] ([id], [id_central], [presion_agua_alta], [presion_agua_media], [presion_agua_baja], [temperatura_gases_entrando_tg], [fecha], [Eficiencia_Camara_Combustion]) VALUES (12029, 1, 3, 4, 5, 6, CAST(0x0000A75A01391C40 AS DateTime), 7)
SET IDENTITY_INSERT [dbo].[TurbinaGas5] OFF

我想在2017-04-19 18：00：00.000和2017-04-19 19：00：00.000之间的两张桌子上获得cada containend

希望你能帮助我，谢谢你

Answer 1

如果您需要每行的数据，无论其他表中是否存在匹配的行，您都应该使用FULL OUTER JOIN和[id_central]执行[fecha]。对于仅具有匹配[fecha]值的行，请使用内部联接。您的查询看起来像这样，具体取决于您需要的内容：

-- All rows with matching fecha

select 
    tg5.presion_agua_alta, 
    tv7.flujo_vapor_alta 
from TurbinaGas5 tg5 
inner join TurbinaVapor7 tv7 
    on tg5.id_central=tv7.id_central
    AND tg5.fecha = tv7.fecha
where tg5.fecha between CONVERT(DATETIME,'2017-04-18 01:50:00',102) and CONVERT(DATETIME,'2017-04-19 09:41:00',102)


-- All rows from TurbinaGas5, and any with matching fecha in TurbinaVapor7

select 
    tg5.presion_agua_alta, 
    tv7.flujo_vapor_alta 
from TurbinaGas5 tg5 
LEFT join TurbinaVapor7 tv7 
    on tg5.id_central=tv7.id_central
    AND tg5.fecha = tv7.fecha
where tg5.fecha between CONVERT(DATETIME,'2017-04-18 01:50:00',102) and CONVERT(DATETIME,'2017-04-19 09:41:00',102)


-- All rows in both tables, matching fecha on the same row

select 
    tg5.presion_agua_alta, 
    tv7.flujo_vapor_alta 
from TurbinaGas5 tg5 
FULL OUTER join TurbinaVapor7 tv7 
    on tg5.id_central=tv7.id_central
    AND tg5.fecha = tv7.fecha
where tg5.fecha between CONVERT(DATETIME,'2017-04-18 01:50:00',102) and CONVERT(DATETIME,'2017-04-19 09:41:00',102)
    or tv7.fecha between CONVERT(DATETIME,'2017-04-18 01:50:00',102) and CONVERT(DATETIME,'2017-04-19 09:41:00',102)

希望这会有所帮助。

从两个表中获取数据，其中不同的列按字段过滤

1 个答案: