sql - 将一个表中的多列连接到另一表中的单列

Question

我希望创建一个 View ，从两个表“Schedule”和“Reference”中提取数据。

Schedule 有 50 多列(它几乎完全非规范化——不是我的设计)，其中大部分包含一个可以连接到 Reference 表中的列的值。

如何编写 SQL 语句以将 Schedules 中的每一列正确连接到 Reference 中的单个列？

Schedule 表定义为:

    CREATE TABLE [dbo].[Schedule](
    [ID] [int] NOT NULL,
    [SCHEDULEWEEK] [datetime] NOT NULL,
    [EMPNO] [numeric](10, 0) NOT NULL,
    [EMPLNAME] [varchar](32) NULL,
    [EMPFNAME] [varchar](32) NULL,
    [EMPSENDATE] [datetime] NULL,
    [EMPHIREDATE] [datetime] NULL,
    [EMPTYPE] [char](1) NULL,
    [EMPSTATUS] [char](1) NULL,
    [SNREFUSALS] [tinyint] NULL,
    [QUALSTRING] [varchar](128) NULL,
    [JOBOVERSHIFTTYPE] [bit] NULL,
    [SHORTNOTICE] [bit] NULL,
    [SHORTNOTICEWAP] [bit] NULL,
    [SHORTNOTICEPHONE] [varchar](32) NULL,
    [LEADHAND] [bit] NULL,
    [DUALCURRENCY] [bit] NULL,
    [MIN100WINDOW] [bit] NULL,
    [STATHOLIDAY] [bit] NULL,
    [AREAOVERHOURS] [bit] NULL,
    [DOUBLEINTERZONES] [bit] NULL,
    [MAXDAYSPERWEEK] [tinyint] NULL,
    [MAXHOURSPERWEEK] [numeric](10, 2) NULL,
    [MAXHOURSPERSHIFT] [numeric](10, 2) NULL,
    [MAXDOUBLESPERWEEK] [tinyint] NULL,
    [ASSIGNEDDAYS] [tinyint] NULL,
    [ASSIGNEDHOURS] [numeric](10, 2) NULL,
    [ASSIGNEDDOUBLES] [tinyint] NULL,
    [ASSIGNEDLOAHOURS] [numeric](10, 2) NULL,
    [SHIFTNO1] [int] NULL,
    [TEXT1_1] [varchar](64) NULL,
    [TEXT2_1] [varchar](64) NULL,
    [DAYFLAG1] [bit] NULL,
    [COMMENT1] [text] NULL,
    [SHIFTNO2] [int] NULL,
    [TEXT1_2] [varchar](64) NULL,
    [TEXT2_2] [varchar](64) NULL,
    [DAYFLAG2] [bit] NULL,
    [COMMENT2] [text] NULL,
    [SHIFTNO3] [int] NULL,
    [TEXT1_3] [varchar](64) NULL,
    [TEXT2_3] [varchar](64) NULL,
    [DAYFLAG3] [bit] NULL,
    [COMMENT3] [text] NULL,
    [SHIFTNO4] [int] NULL,
    [TEXT1_4] [varchar](64) NULL,
    [TEXT2_4] [varchar](64) NULL,
    [DAYFLAG4] [bit] NULL,
    [COMMENT4] [text] NULL,
    [SHIFTNO5] [int] NULL,
    [TEXT1_5] [varchar](64) NULL,
    [TEXT2_5] [varchar](64) NULL,
    [DAYFLAG5] [bit] NULL,
    [COMMENT5] [text] NULL,
    [SHIFTNO6] [int] NULL,
    [TEXT1_6] [varchar](64) NULL,
    [TEXT2_6] [varchar](64) NULL,
    [DAYFLAG6] [bit] NULL,
    [COMMENT6] [text] NULL
-- Snip
) ON [PRIMARY]

引用表定义为:

CREATE TABLE [dbo].[Reference](
    [ID] [int] NOT NULL,
    [CODE] [varchar](21) NOT NULL,
    [LOCATIONCODE] [varchar](4) NOT NULL,
    [SCHAREACODE] [varchar](16) NOT NULL,
    [LOCATIONNAME] [varchar](32) NOT NULL,
    [FLTAREACODE] [varchar](16) NOT NULL
) ON [PRIMARY]

我试图将附表中的每个 [TEXT1_]/[TEXT2_] 列加入引用中的 [SCHAREACODE] 列。所有引用表包含的是员工可以工作的区域列表。

Answer 1

我认为他的意思是多次加入 Reference 表:

SELECT *
  FROM Schedule AS S
 INNER JOIN Reference AS R1 
         ON R1.ID = S.FirstID 
 INNER JOIN Reference AS R2 
         ON R2.ID = S.SecondID 
 INNER JOIN Reference AS R3 
         ON R3.ID = S.ThirdID 
 INNER JOIN Reference AS R4 
         ON R4.ID = S.ForthID