我如何 "Update Select" 具有子查询的列中的某些值？
How can I "Update Select" some values in a column with a subquery?
我正在使用 Apache Derby DB (SQL) 版本 10.14，这是 Derby 参考手册：https://db.apache.org/derby/docs/10.14/ref/refderby.pdf
我正在尝试创建星型模式，目前正在研究区域维度 table。
这些是我正在使用的 table：
DWH_PRICE_PAID_RECORDS
TRANSACTION_ID PRICE DATE_OF_TRANSFER PROPERTY_TYPE OLD_NEW DURATION TOWN_CITY DISTRICT COUNTY PPDCATEGORY_TYPE RECORD_TYPE
{FDD12C8B-5A02-4B3F-8C67-9BC523DC780B} 71000 15.09.2000 00:00 D N F SCUNTHORPE NORTH LINCOLNSHIRE NORTH LINCOLNSHIRE A A
{70F7F480-4A9A-4FEB-A58A-2B964605BFD2} 97000 01.08.2002 00:00 F N L MANCHESTER SALFORD GREATER MANCHESTER A A
{64D48FA9-8C85-49D6-AF5A-23FABDDB4FEB} 104000 17.01.2006 00:00 S N L ROCHDALE ROCHDALE GREATER MANCHESTER A A
{F0316F65-E375-4DC4-BCDF-3FDC054ADE9C} 188500 18.05.2015 00:00 S N F KIDDERMINSTER MALVERN HILLS WORCESTERSHIRE A A
{2EC5A85B-7BEF-4127-B3D0-6B416899CAEB} 180000 07.05.1999 00:00 S N F KINGSTON UPON THAMES KINGSTON UPON THAMES GREATER LONDON A A
{21E5FEB7-A62E-2439-E050-A8C06205342E} 55000 28.08.2015 00:00 T N F MOUNTAIN ASH RHONDDA CYNON TAFF RHONDDA CYNON TAFF B A
{3E0330F0-0F44-8D89-E050-A8C062052140} 77000 30.08.2016 00:00 T N F WALLASEY WIRRAL MERSEYSIDE A A
{D43A8B4A-6272-4706-9189-30F8E24EDF13} 210000 23.05.2007 00:00 S N F BRISTOL NORTH SOMERSET NORTH SOMERSET A A
{3575DAF5-0E80-408F-9970-FDF5D1475E73} 185000 16.11.2007 00:00 S N F CREWKERNE SOUTH SOMERSET SOMERSET A A
{A4246390-61F4-4228-BC82-79D3F369CA34} 32700 12.12.1996 00:00 F N L SOUTHAMPTON SOUTHAMPTON SOUTHAMPTON A A
CREATE TABLE "DWH_PRICE_PAID_RECORDS" ("TRANSACTION_ID" VARCHAR(50) NOT NULL, "PRICE" INTEGER, "DATE_OF_TRANSFER" DATE NOT NULL, "PROPERTY_TYPE" CHAR(1), "OLD_NEW" CHAR(1), "DURATION" CHAR(1), "TOWN_CITY" VARCHAR(50), "DISTRICT" VARCHAR(50), "COUNTY" VARCHAR(50), "PPDCATEGORY_TYPE" CHAR(1), "RECORD_TYPE" CHAR(1));
DWH_POSTCODES
Postcode Eastings Northings Latitude Longitude Town Region UK_Region Country_Code Country_String
AB10 392900 804900 5,713,514 -211,731 Aberdeen Aberdeen City Scotland SCT Scotland
AB13 385600 801900 5,710,801 -223,776 Milltimber Aberdeen City Scotland SCT Scotland
AB14 383600 801100 5,710,076 -227,073 Peterculter Aberdeen City Scotland SCT Scotland
AB21 387900 813200 572,096 -220,033 Aberdeen Airport Aberdeen City Scotland SCT Scotland
AB22 392800 810700 5,718,724 -211,913 Bridge of Don Aberdeen City Scotland SCT Scotland
AB30 370900 772900 5,684,678 -247,712 Laurencekirk Aberdeenshire Scotland SCT Scotland
AB31 368100 798300 5,707,479 -252,623 Banchory Aberdeenshire Scotland SCT Scotland
AB32 380800 807200 5,715,545 -231,742 Westhill Aberdeenshire Scotland SCT Scotland
AB33 355200 815100 5,722,464 -274,203 Alford Aberdeenshire Scotland SCT Scotland
AB34 350800 800600 5,709,393 -281,204 Aboyne Aberdeenshire Scotland SCT Scotland
CREATE TABLE "DWH_POSTCODES" ("POSTCODE_ID" INTEGER generated always as identity (start with 1 increment by 1), "POSTCODE" VARCHAR(10), "EASTINGS" VARCHAR(50), "NORTHINGS" VARCHAR(50), "LATITUDE" VARCHAR(10), "LONGITUDE" VARCHAR(10), "TOWN" VARCHAR(50) NOT NULL, "REGION" VARCHAR(50), "UK_REGION" VARCHAR(50), "COUNTRY_CODE" VARCHAR(20), "COUNTRY_STRING" VARCHAR(20));
和DIM_REGION
CREATE TABLE "DIM_REGION" ("REGION_ID" INTEGER generated always as identity (start with 1 increment by 1), "TOWN" VARCHAR(30), "COUNTY" VARCHAR(30), "DISTRICT" VARCHAR(30), "LATITUDE" VARCHAR(10), "LONGITUDE" VARCHAR(10), "COUNTRY_STRING" VARCHAR(20));
首先我插入了镇（唯一）、县和区：
INSERT INTO DIM_REGION (TOWN, County, District) SELECT town_city, MAX(county), MAX(district) FROM DWH_PRICE_PAID_RECORDS GROUP BY town_city;
城镇必须是唯一的，因为我没有任何其他东西作为 match/link table 的标识符。 DIM_REGION table 现在有 938 个独特的城镇记录，我想 "UPDATE" 剩余的列 "Latitude"、"Longitude" 和 "COUNTRY_STRING"。 DWH_POSTCODES table 有1637个独特的城镇记录，这意味着城镇是不同的！只有 532 个城镇匹配，只有那些应在 DIM_REGION table 中更新。
我只从一列开始 "Latitude"，这就是我希望它在更新语句之后的样子：
UPDATE DIM_REGION SET DIM_REGION.LATITUDE = (SELECT DWH_POSTCODES.LATITUDE from dim_region join dwh_postcodes on dim_region.town = dwh_postcodes.town where dim_region.town = dwh_postcodes.town);
但是当我这样做时，我收到了这个错误信息（错误信息是德语，我不得不翻译，抱歉）：
ERROR 21000 a scalar subquery returned more than one value
我不明白为什么。如果我只提交 select 语句：
SELECT DWH_POSTCODES.LATITUDE from dim_region join dwh_postcodes on dim_region.town = dwh_postcodes.town where dim_region.town = dwh_postcodes.town
我得到的正是我期望得到的，这就是所有纬度的整个专栏。
非常感谢！
当您需要更新多行时使用下面的查询。
UPDATE A SET A.LATITUDE = B.LATITUDE
FROM DIM_REGION as A JOIN DWH_POSTCODES B
ON A.TOWN = B.TOWN
WHERE A.TOWN = B.TOWN
您收到的错误是因为您的子查询返回了超过 1 条记录。您需要将子查询的结果限制为 1。否则，它将不起作用。
或者，您可以将子查询与 TOP 1
一起使用
UPDATE DIM_REGION SET DIM_REGION.LATITUDE = (SELECT TOP 1 DWH_POSTCODES.LATITUDE from dim_region join dwh_postcodes on dim_region.town = dwh_postcodes.town where dim_region.town = dwh_postcodes.town);
希望这对您有所帮助。
@flippi
在一个块中执行多个更新语句的一种方法：
BEGIN
UPDATE ...
UPDATE ...
UPDATE ...
...
END;
IBM Db2和Apache Derby DB是完全不同的产品。因此，删除 db2 标签。
您在两个表中都提供了 non-matched 个城镇列表。准备匹配的数据集有那么难吗？
如果 dwh_postcodes.town 列中没有重复项，则 update 应如下所示（可能与 EXISTS 谓词中的 subselect 相同在 WHERE):
UPDATE DIM_REGION SET DIM_REGION.LATITUDE =
(
SELECT
--MAX (
DWH_POSTCODES.LATITUDE
--)
from dwh_postcodes
where dim_region.town = dwh_postcodes.town
-- fetch first 1 row only
)
/*
WHERE EXISTS
(
SELECT 1
from dwh_postcodes
where dim_region.town = dwh_postcodes.town
)
*/
;
否则你必须使用一些聚合函数（或者 fetch first 子句，如果 Derby 支持的话）来使这个 subselect return 只有 1 行，如示例中注释掉的那样以上。
或者，您可以执行 1 次 INSERT 而不是 INSERT 和 UPDATE 来填充所有 4 列：
INSERT INTO DIM_REGION (TOWN, County, District, latitude)
SELECT p.town_city, p.county, p.district, d.latitude
FROM (
SELECT town_city, MAX(county) county, MAX(district) district
FROM DWH_PRICE_PAID_RECORDS
GROUP BY town_city
) p
join dwh_postcodes d on p.town_city = d.town;
我正在使用 Apache Derby DB (SQL) 版本 10.14，这是 Derby 参考手册：https://db.apache.org/derby/docs/10.14/ref/refderby.pdf
我正在尝试创建星型模式，目前正在研究区域维度 table。
这些是我正在使用的 table：
DWH_PRICE_PAID_RECORDS
TRANSACTION_ID PRICE DATE_OF_TRANSFER PROPERTY_TYPE OLD_NEW DURATION TOWN_CITY DISTRICT COUNTY PPDCATEGORY_TYPE RECORD_TYPE
{FDD12C8B-5A02-4B3F-8C67-9BC523DC780B} 71000 15.09.2000 00:00 D N F SCUNTHORPE NORTH LINCOLNSHIRE NORTH LINCOLNSHIRE A A
{70F7F480-4A9A-4FEB-A58A-2B964605BFD2} 97000 01.08.2002 00:00 F N L MANCHESTER SALFORD GREATER MANCHESTER A A
{64D48FA9-8C85-49D6-AF5A-23FABDDB4FEB} 104000 17.01.2006 00:00 S N L ROCHDALE ROCHDALE GREATER MANCHESTER A A
{F0316F65-E375-4DC4-BCDF-3FDC054ADE9C} 188500 18.05.2015 00:00 S N F KIDDERMINSTER MALVERN HILLS WORCESTERSHIRE A A
{2EC5A85B-7BEF-4127-B3D0-6B416899CAEB} 180000 07.05.1999 00:00 S N F KINGSTON UPON THAMES KINGSTON UPON THAMES GREATER LONDON A A
{21E5FEB7-A62E-2439-E050-A8C06205342E} 55000 28.08.2015 00:00 T N F MOUNTAIN ASH RHONDDA CYNON TAFF RHONDDA CYNON TAFF B A
{3E0330F0-0F44-8D89-E050-A8C062052140} 77000 30.08.2016 00:00 T N F WALLASEY WIRRAL MERSEYSIDE A A
{D43A8B4A-6272-4706-9189-30F8E24EDF13} 210000 23.05.2007 00:00 S N F BRISTOL NORTH SOMERSET NORTH SOMERSET A A
{3575DAF5-0E80-408F-9970-FDF5D1475E73} 185000 16.11.2007 00:00 S N F CREWKERNE SOUTH SOMERSET SOMERSET A A
{A4246390-61F4-4228-BC82-79D3F369CA34} 32700 12.12.1996 00:00 F N L SOUTHAMPTON SOUTHAMPTON SOUTHAMPTON A A
CREATE TABLE "DWH_PRICE_PAID_RECORDS" ("TRANSACTION_ID" VARCHAR(50) NOT NULL, "PRICE" INTEGER, "DATE_OF_TRANSFER" DATE NOT NULL, "PROPERTY_TYPE" CHAR(1), "OLD_NEW" CHAR(1), "DURATION" CHAR(1), "TOWN_CITY" VARCHAR(50), "DISTRICT" VARCHAR(50), "COUNTY" VARCHAR(50), "PPDCATEGORY_TYPE" CHAR(1), "RECORD_TYPE" CHAR(1));
DWH_POSTCODES
Postcode Eastings Northings Latitude Longitude Town Region UK_Region Country_Code Country_String
AB10 392900 804900 5,713,514 -211,731 Aberdeen Aberdeen City Scotland SCT Scotland
AB13 385600 801900 5,710,801 -223,776 Milltimber Aberdeen City Scotland SCT Scotland
AB14 383600 801100 5,710,076 -227,073 Peterculter Aberdeen City Scotland SCT Scotland
AB21 387900 813200 572,096 -220,033 Aberdeen Airport Aberdeen City Scotland SCT Scotland
AB22 392800 810700 5,718,724 -211,913 Bridge of Don Aberdeen City Scotland SCT Scotland
AB30 370900 772900 5,684,678 -247,712 Laurencekirk Aberdeenshire Scotland SCT Scotland
AB31 368100 798300 5,707,479 -252,623 Banchory Aberdeenshire Scotland SCT Scotland
AB32 380800 807200 5,715,545 -231,742 Westhill Aberdeenshire Scotland SCT Scotland
AB33 355200 815100 5,722,464 -274,203 Alford Aberdeenshire Scotland SCT Scotland
AB34 350800 800600 5,709,393 -281,204 Aboyne Aberdeenshire Scotland SCT Scotland
CREATE TABLE "DWH_POSTCODES" ("POSTCODE_ID" INTEGER generated always as identity (start with 1 increment by 1), "POSTCODE" VARCHAR(10), "EASTINGS" VARCHAR(50), "NORTHINGS" VARCHAR(50), "LATITUDE" VARCHAR(10), "LONGITUDE" VARCHAR(10), "TOWN" VARCHAR(50) NOT NULL, "REGION" VARCHAR(50), "UK_REGION" VARCHAR(50), "COUNTRY_CODE" VARCHAR(20), "COUNTRY_STRING" VARCHAR(20));
和DIM_REGION
CREATE TABLE "DIM_REGION" ("REGION_ID" INTEGER generated always as identity (start with 1 increment by 1), "TOWN" VARCHAR(30), "COUNTY" VARCHAR(30), "DISTRICT" VARCHAR(30), "LATITUDE" VARCHAR(10), "LONGITUDE" VARCHAR(10), "COUNTRY_STRING" VARCHAR(20));
首先我插入了镇（唯一）、县和区：
INSERT INTO DIM_REGION (TOWN, County, District) SELECT town_city, MAX(county), MAX(district) FROM DWH_PRICE_PAID_RECORDS GROUP BY town_city;
城镇必须是唯一的，因为我没有任何其他东西作为 match/link table 的标识符。 DIM_REGION table 现在有 938 个独特的城镇记录，我想 "UPDATE" 剩余的列 "Latitude"、"Longitude" 和 "COUNTRY_STRING"。 DWH_POSTCODES table 有1637个独特的城镇记录，这意味着城镇是不同的！只有 532 个城镇匹配，只有那些应在 DIM_REGION table 中更新。
我只从一列开始 "Latitude"，这就是我希望它在更新语句之后的样子：
UPDATE DIM_REGION SET DIM_REGION.LATITUDE = (SELECT DWH_POSTCODES.LATITUDE from dim_region join dwh_postcodes on dim_region.town = dwh_postcodes.town where dim_region.town = dwh_postcodes.town);
但是当我这样做时，我收到了这个错误信息（错误信息是德语，我不得不翻译，抱歉）：
ERROR 21000 a scalar subquery returned more than one value
我不明白为什么。如果我只提交 select 语句：
SELECT DWH_POSTCODES.LATITUDE from dim_region join dwh_postcodes on dim_region.town = dwh_postcodes.town where dim_region.town = dwh_postcodes.town
我得到的正是我期望得到的，这就是所有纬度的整个专栏。
非常感谢！
当您需要更新多行时使用下面的查询。
UPDATE A SET A.LATITUDE = B.LATITUDE
FROM DIM_REGION as A JOIN DWH_POSTCODES B
ON A.TOWN = B.TOWN
WHERE A.TOWN = B.TOWN
您收到的错误是因为您的子查询返回了超过 1 条记录。您需要将子查询的结果限制为 1。否则，它将不起作用。
或者，您可以将子查询与 TOP 1
一起使用UPDATE DIM_REGION SET DIM_REGION.LATITUDE = (SELECT TOP 1 DWH_POSTCODES.LATITUDE from dim_region join dwh_postcodes on dim_region.town = dwh_postcodes.town where dim_region.town = dwh_postcodes.town);
希望这对您有所帮助。
@flippi
在一个块中执行多个更新语句的一种方法：
BEGIN
UPDATE ...
UPDATE ...
UPDATE ...
...
END;
IBM Db2和Apache Derby DB是完全不同的产品。因此，删除 db2 标签。
您在两个表中都提供了 non-matched 个城镇列表。准备匹配的数据集有那么难吗？
如果 dwh_postcodes.town 列中没有重复项，则 update 应如下所示（可能与 EXISTS 谓词中的 subselect 相同在 WHERE):
UPDATE DIM_REGION SET DIM_REGION.LATITUDE =
(
SELECT
--MAX (
DWH_POSTCODES.LATITUDE
--)
from dwh_postcodes
where dim_region.town = dwh_postcodes.town
-- fetch first 1 row only
)
/*
WHERE EXISTS
(
SELECT 1
from dwh_postcodes
where dim_region.town = dwh_postcodes.town
)
*/
;
否则你必须使用一些聚合函数（或者 fetch first 子句，如果 Derby 支持的话）来使这个 subselect return 只有 1 行，如示例中注释掉的那样以上。
或者，您可以执行 1 次 INSERT 而不是 INSERT 和 UPDATE 来填充所有 4 列：
INSERT INTO DIM_REGION (TOWN, County, District, latitude)
SELECT p.town_city, p.county, p.district, d.latitude
FROM (
SELECT town_city, MAX(county) county, MAX(district) district
FROM DWH_PRICE_PAID_RECORDS
GROUP BY town_city
) p
join dwh_postcodes d on p.town_city = d.town;