SQL语法SELECT和Sub SELECT和JOIN

问题描述

我有一个SELECT语句（e），它产生一个结果集。我想将结果集减少为仅数据的最新版本，因此我在选择的末尾放置了一个WHERE子句，其内容为WHERE e.[Version] = (SELECT MAX(e.[Version]) FROM [dbo].[d_bpcunits])。 然后，我JOIN将另一个表（f） LEFT JOIN [dbo].[d_bpc] as f on e.[bu_product_code] = f.idbpc设置为记录集，因为我希望从主表中显示一致的数据，而不是用户输入的不一致的信息。然后，我使用（f）中的许多字段替换（e）中的字段，这将产生我想要的干净数据集。

这是我打算UNION ALL一起使用的4个结果集之一，以便我可以用于大型分析。

我正在运行sql Server 14.0。

我的选择查询如下：

SELECT
e.[bu_product_code] AS ProductCode,f.[bpc_desc] AS Description,NULL AS BPCCountry,f.[bpc_business_nature] AS BusinessNature,e.[bu_year_month] AS YearMonth,f.[bpc_active_ingredient] AS ActiveIngredient,f.[bpc_ai_content] AS AIContent,f.[bpc_formulation_type] AS FormulationType,f.[bpc_brand] AS Brand,f.[bpc_min_pack] AS MinPack,f.[bpc_product_category] AS ProductCategory,e.[bu_entity] AS Entity,e.[bu_ship_to_ctry] AS ShipToCtry,e.[bu_ccy] AS CCY,e.[bu_data_type] AS DataType,NULL AS ProductType,e.[bu_latest] AS Latest,e.[Version] AS Version,e.[bu_account] AS UAccount,e.[bu_entity_code] AS UEntityCode,e.[bu_interco_code] AS UIntercoCode,e.[bu_pic] AS Upic,e.[bu_source] AS USource,e.[bu_sales_rep] AS USalesRep,e.[bu_qty_type] AS UQtyType,e.[bu_amount] AS UAmount
FROM
[dbo].[d_bpcunits] e
LEFT JOIN [dbo].[d_bpc] as f on e.[bu_product_code] = f.idbpc
WHERE e.[Version] = (SELECT MAX(e.[Version]) FROM [dbo].[d_bpcunits])

谢谢您的帮助。

解决方法

我在查询中看到的唯一问题是最后一行

  --SELECT MAX(e.[Version]) FROM [dbo].[d_bpcunits]

需要更改为

    SELECT MAX([Version]) FROM [dbo].[d_bpcunits]

然后查询变为

SELECT
e.[bu_product_code] AS ProductCode,f.[bpc_desc] AS Description,NULL AS BPCCountry,f.[bpc_business_nature] AS BusinessNature,e.[bu_year_month] AS YearMonth,f.[bpc_active_ingredient] AS ActiveIngredient,f.[bpc_ai_content] AS AIContent,f.[bpc_formulation_type] AS FormulationType,f.[bpc_brand] AS Brand,f.[bpc_min_pack] AS MinPack,f.[bpc_product_category] AS ProductCategory,e.[bu_entity] AS Entity,e.[bu_ship_to_ctry] AS ShipToCtry,e.[bu_ccy] AS CCY,e.[bu_data_type] AS DataType,NULL AS ProductType,e.[bu_latest] AS Latest,e.[Version] AS Version,e.[bu_account] AS UAccount,e.[bu_entity_code] AS UEntityCode,e.[bu_interco_code] AS UIntercoCode,e.[bu_pic] AS Upic,e.[bu_source] AS USource,e.[bu_sales_rep] AS USalesRep,e.[bu_qty_type] AS UQtyType,e.[bu_amount] AS UAmount
FROM
[dbo].[d_bpcunits] e
LEFT JOIN [dbo].[d_bpc] as f on e.[bu_product_code] = f.idbpc
WHERE e.[Version] = (SELECT MAX([Version]) FROM [dbo].[d_bpcunits])