我正在尝试根据与另一个表的匹配来更新表，但出现多部分标识符错误

Question

I am having an issue with trying to update a table with values from another table when a match doesn't exist. Here is the scenario, I have a participation table that has about 250K records. I need to find the legislative districts associated with the records based on a zip + 4 code. My participation table has the zip and the zip4 codes. Sometimes I have both, sometimes neither. Gotta love data sets like this. I have a second table which contains all of the legislative districts by 9 digit zip codes. I have updated the data set and included the individual zip and zip4 codes. Here is the code that I have:

update 
        [ComEd].[dbo].[PP_FFR_BU]
set
        [Zip4] =
(
    CASE
        when
            [Tim].[dbo].[PP_FFR_BU].[Zip] + [Tim].[dbo].[PP_FFR_BU].[Zip4] not in (select zip from [TimCIS].[dbo].[Legis_Districts])
        then 
        CASE
            when [Tim].[dbo].[PP_FFR_BU].[Zip] = [TimCIS].[dbo].[Legis_Districts].[Zip5] and [Tim].[dbo].[PP_FFR_BU].[Zip4] <> [TimCIS].[dbo].[Legis_Districts].[Zip4]
            then (select top 1 [ComEdCIS].[dbo].[Legis_Districts].[Zip4] from [TimCIS].[dbo].[Legis_Districts] where [Tim].[dbo].[PP_FFR_BU].[Zip] = [TimCIS].[dbo].[Legis_Districts].[Zip5])
            when len([Tim].[dbo].[PP_FFR_BU].[Zip])<5 
            then '0000'
        end
    end
)
where 
    [Tim].[dbo].[PP_FFR_BU].[Zip] + [Tim].[dbo].[PP_FFR_BU].[Zip4] not in (select zip from [TimCIS].[dbo].[Legis_Districts])

Now I am getting an error:

Msg 4104, Level 16, State 1, Line 11 The multi-part identifier "TimCIS.dbo.Legis_Districts.Zip4" could not be bound. Which equates to the when clause in the second CASE statement.

If the zip and zip4 in the original table are in the legislative district table then I need to move to the next record. If the zip is in the table and the zip4 doesn't match, I need the first value that matches. If the zip doesn't exist in the legislative table then I want to put a '0000' in the zip4 of the participation table. Any insight would be greatly appreciated.

Answer 1

In the case statement you have this query:

then (select top 1 [ComEdCIS].[dbo].[Legis_Districts].[Zip4] from [TimCIS].[dbo].[Legis_Districts] where [Tim].[dbo].[PP_FFR_BU].[Zip] = [TimCIS].[dbo].[Legis_Districts].[Zip5])

But this part doesn't make sense:

select top 1 [ComEdCIS].[dbo].[Legis_Districts].[Zip4] from [TimCIS].[dbo].[Legis_Districts]

You are selecting a column from a table that isn't in your from clause. They are in two different databases.