SQL Server: Update table row using merge

Question

Hello I am using trying to update a table from dynamic variable but I always got Incorrect syntax, can you help me where did I made a mistake?

This is the message when I run the query.

select convert(varchar(55),refdate)+'-'+convert(varchar(55),refcount) FROM [gen_048_MAR2016]

  MERGE gen_048_MAR2016 as target USING #temp1 as source ON target.refcount = source.refnum AND sourc3e.tsql = target.refcount WHEN MATCHED THEN UPDATE SET target.stat = source.stat target.statdate = source.statdate WHEN NOT MATCHED BY TARGET THEN INSERT (stat, statdate) VALUES (S.stat, S.statdate) ; Msg 102, Level 15, State 1, Line 10 Incorrect syntax near 'target'. 

ERROR: Incorrect syntax near 'target'.

I didn't write the whole query so I just copy and paste the party where I think I made an error.

CREATE TABLE #records(
         [index] int PRIMARY KEY IDENTITY
        ,refnum varchar(200)
        ,stat varchar(200)
        ,statdate varchar(200)
    )

insert into #records (refnum, stat, statdate) 
select 
dbo.fn_Parsename(WHOLEROW,'|',0),
dbo.fn_Parsename(WHOLEROW,'|',3),
dbo.fn_Parsename(WHOLEROW,'|',4)

from #temp1

declare @refnum varchar(100)
declare @stat varchar(100)
declare @statdate varchar(100)
declare @sql NVARCHAR(MAX),
declare @index int


WHILE (@index <= (SELECT MAX([index]) FROM #records))


    BEGIN

    set @stat = (select stat from #records where [index] = @index)
    select @stat
    set @statdate = (select statdate from #records where [index] = @index)
    select @statdate

    set @refnum = (select refnum from #records where [index] = @index)
    set @refnum = replace(@refnum, 'F', '')
    select @refnum

    set @sql = '
        MERGE '+@sourceTable+' T
        USING #temp1 S
            ON T.refcount = S.refnum
                AND S.tsql = T.refcount
        WHEN MATCHED THEN
            UPDATE
                SET 
                T.stat = S.stat
                T.statdate = S.statdate
        WHEN NOT MATCHED BY TARGET THEN
          INSERT (stat, statdate)
          VALUES (S.stat, S.statdate)                   
            ;'
            select @refnum, @stat, @statdate
            print @sql
            exec (@sql)

        SELECT 'File has been successfully uploaded', @fileDate,'success' as msg

      set @index = @index + 1

   END

I didn't put the @sourceTable string to lessen the codes, but I can add it anytime if that info is needed.

Answer 1

1. In your actual dynamic SQL after variable substitution you use target and source reserved words as table aliases. Use square brackets [target] or better still just T as you do in "the whole query" code sample.
2. You are missing comma in dynamic SQL after T.stat = S.stat .