Question

我试图在8个表之间建立连接，并且因为每个表有超过500,000个条目，所以它非常慢。我想知道，你有没有最好的方式加入这些表？

所有表都具有以下结构：

data_temprature：

+----+----------+-----+-----------+----------+
| ID_geo | NAME     | Value | Date            |
+--------+----------+-------+-----------------+
|  10005 | Madrid   |  32   | 2017-06-12 08:00|
|  10005 | Madrid   |  25   | 2017-06-12 09:00|
|  12701 | Paris    |  23   | 2017-06-12 08:00|
|  13006 | Tokyo    |  25   | 2017-06-12 11:00|
|  11132 | Sevilla  |  27   | 2017-06-12 16:00|
|  21333 | London   |  22   | 2017-06-12 17:00|
+--------+----------+-------+-----------------+

data_WeatherSimbol

+----+----------+-----+-----------+----------+
| ID_geo | NAME     | Value | Date            |
+--------+----------+-------+-----------------+
|  10005 | Madrid   |  A+   | 2017-06-12 08:00|
|  10005 | Madrid   |  A    | 2017-06-12 09:00|
|  12701 | Paris    |  A-   | 2017-06-12 08:00|
|  13006 | Tokyo    |  C-   | 2017-06-12 11:00|
|  11132 | Sevilla  |  I+   | 2017-06-12 16:00|
|  21333 | London   |  D-   | 2017-06-12 17:00|
+--------+----------+-------+-----------------+

我想加入以获得这个结果：

+----+----------+-----+-----------+----------+-----------------+
| ID_geo | NAME     | Temperature | Simboles |      Date       |
+--------+----------+-------------+----------+-----------------+
|  10005 | Madrid   |      32     |    A+    | 2017-06-12 08:00|
|  10005 | Madrid   |      25     |    A     | 2017-06-12 09:00|
|  12701 | Paris    |      23     |    A-    | 2017-06-12 08:00|
|  13006 | Tokyo    |      25     |    C-    | 2017-06-12 11:00|
|  11132 | Sevilla  |      27     |    I+    | 2017-06-12 16:00|
|  21333 | London   |      22     |    D-    | 2017-06-12 17:00|
+--------+----------+-------------+----------+-----------------+

由于

提供更新实际数据：

执行计划： https://files.fm/u/b4besk27

这是查询：

    SELECT
    cielo.data_value AS cielo,
    lluv.data_value AS lluvia,
  temp.data_value AS temp,
  vientos.data_value AS viento,
  tmin.data_value AS tempmin,
  tmax.data_value AS tempmax, 
    cielo.data_date AS DiaPrev
FROM
    data_cielo AS cielo
INNER JOIN data_lluvia AS lluv ON cielo.data_geo = lluv.data_geo
INNER JOIN data_presion AS pres ON cielo.data_geo = pres.data_geo
INNER JOIN data_temp AS temp ON cielo.data_geo = temp.data_geo
LEFT JOIN data_tempmax AS tmax ON cielo.data_geo = tmax.data_geo
LEFT JOIN data_tempmin AS tmin ON cielo.data_geo = tmin.data_geo
INNER JOIN data_viento AS vientos ON cielo.data_geo = vientos.data_geo

WHERE
    cielo.data_date = lluv.data_date
AND pres.data_date = cielo.data_date
AND vientos.data_date = pres.data_date
AND temp.data_date = vientos.data_date
AND cielo.data_geo = 46 ORDER BY cielo.data_date;
and this is the result:

E+  0.0461028   29.6937088  S2  19.408  36.39   2017-06-13 12:00:00.000
E+  0.0461028   29.6937088  S2  21.422  36.39   2017-06-13 12:00:00.000
E+  0.0461028   29.6937088  S2  19.408  37.853  2017-06-13 12:00:00.000
E+  0.0461028   29.6937088  S2  21.422  37.853  2017-06-13 12:00:00.000
E+  0.0461028   30.7593854  S2  19.408  36.39   2017-06-13 13:00:00.000
E+  0.0461028   30.7593854  S2  21.422  36.39   2017-06-13 13:00:00.000
E+  0.0461028   30.7593854  S2  19.408  37.853  2017-06-13 13:00:00.000
E+  0.0461028   30.7593854  S2  21.422  37.853  2017-06-13 13:00:00.000
A+  0.0461028   31.6310774  SSW2    19.408  36.39   2017-06-13 14:00:00.000
A+  0.0461028   31.6310774  SSW2    21.422  36.39   2017-06-13 14:00:00.000
A+  0.0461028   31.6310774  SSW2    19.408  37.853  2017-06-13 14:00:00.000
A+  0.0461028   31.6310774  SSW2    21.422  37.853  2017-06-13 14:00:00.000
A   0.0461028   32.2647927  S2  19.408  36.39   2017-06-13 15:00:00.000
A   0.0461028   32.2647927  S2  21.422  36.39   2017-06-13 15:00:00.000
A   0.0461028   32.2647927  S2  19.408  37.853  2017-06-13 15:00:00.000

它不应该像这样，我需要像我所说的每小时温度，压力，降水，天空......的数据值......

Answer 1

试试这个

;With data_temprature(ID_geo,NAME,Value,[Date])
AS
(
SELECT  10005 , 'Madrid'   ,  32   , '2017-06-12 08:00' Union all
SELECT  10005 , 'Madrid'   ,  25   , '2017-06-12 09:00' Union all
SELECT  12701 , 'Paris'    ,  23   , '2017-06-12 08:00' Union all
SELECT  13006 , 'Tokyo'    ,  25   , '2017-06-12 11:00' Union all
SELECT  11132 , 'Sevilla'  ,  27   , '2017-06-12 16:00' Union all
SELECT  21333 , 'London'   ,  22   , '2017-06-12 17:00' 
)
,data_WeatherSimbol(ID_geo,NAME,Value,[Date])
AS
(
SELECT  10005 , 'Madrid'   ,  'A+'   , '2017-06-12 08:00' Union all
SELECT  10005 , 'Madrid'   ,  'A'   ,  '2017-06-12 09:00' Union all
SELECT  12701 , 'Paris'    ,  'A-'   , '2017-06-12 08:00' Union all
SELECT  13006 , 'Tokyo'    ,  'C-'   , '2017-06-12 11:00' Union all
SELECT  11132 , 'Sevilla'  ,  'I+'   , '2017-06-12 16:00' Union all
SELECT  21333 , 'London'   ,  'D-'   , '2017-06-12 17:00' 
)
SELECT ID_geo,
       NAME,
       Temperature,
       Symboles,
       [Date]  From 
(
SELECT t.ID_geo ,
        t.NAME ,
        t.Value AS Temperature,
        w.Value AS Symboles,t.[Date] ,
        ROW_NUMBER()OVER(PARTITION BY t.Value,t.[Date] ORDER BY t.[Date]) AS Rno
 FROM data_temprature t
INNER join data_WeatherSimbol w
On t.ID_geo=w.ID_geo
)Dt 
WHERE Dt.Rno=1
ORDER BY ID_geo

Answer 2

我认为您可以加入地理位置和日期：

select t.*, ws.simboles
from data_temperature t join
     data_WeatherSimbol ws
     on t.ID_geo = ws.ID_geo and t.date = ws.date;

Answer 3

[ID_geo]和[Date]似乎都不足以加入，所以：

为所有表格（如
）的两列创建索引
create index IX_data_temprature on data_temprature ([ID_geo], [Date])
按[ID_geo]，[Date]

Answer 4

查询的大部分负载都是由RID查找引起的。

当索引不覆盖查询时（Sql必须查找表中的值，因为它们未包含在索引中）并且索引是非群集的，因此使用RID查找。

如果使用覆盖索引，查询可能会更快，您可能没有在索引中包含值。有关包含的更多信息，请参阅Microsoft docs。

如果将非聚集索引更改为聚簇索引，也可能会有所帮助。

加入具有相同结构但数据不同的多个表

4 个答案: