Первые 25 столбцов в табличном запросе встроены в @query и затем выполняются. Подставьте правильное значение @target_table.
DECLARE
@target_table sysname
, @query nvarchar(max)
SET
@target_table = '_dimAreaOverlay'
; with of_interest as
(
SELECT
SS.name AS schemaname
, T.name AS tablename
, SC.name AS columname
FROM
sys.schemas SS
inner join
sys.tables T
ON T.schema_id = SS.schema_id
inner join
sys.columns SC
ON SC.object_id = T.object_id
WHERE
T.name = @target_table
AND SC.column_id < 26
)
, c AS
(
SELECT
STUFF((
SELECT
',' + QUOTENAME(I.columname)
FROM
of_interest I
FOR XML PATH('')), 1,1, '') AS column_list
, OI.tablename
, OI.schemaname
FROM
of_interest OI
GROUP BY
OI.schemaname
, OI.tablename
)
SELECT
@query = 'SELECT '
+ C.column_list
+ ' FROM '
+ QUOTENAME(C.schemaname)
+ '.'
+ QUOTENAME(C.tablename)
FROM C
EXECUTE(@query)