StackOverFlow42109425, Sql Server

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DECLARE @Table1 as table (
      [ID] [bigint]
    , [RecTime] [datetime]
)
DECLARE @Table2 as table (
      [ID] [bigint]
    , [RecTime] [datetime]
)
DECLARE @Table3 as table (
      [ID] [bigint]
    , [RecTime] [datetime]
)

DECLARE @Files as table (
      [ID] [bigint]
    , [tblName] nvarchar(255) NULL
    , [tblID] bigint NULL
    , [BinaryData]  varbinary(max)
    /* and some other columns */
)

INSERT INTO @Table1 (
      [ID]
    , [RecTime]
)
          SELECT '1', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '2', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '3', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '4', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '5', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)

INSERT INTO @Table2 (
      [ID]
    , [RecTime]
)
          SELECT '11', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '12', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '13', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '14', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '15', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)

INSERT INTO @Table3 (
      [ID]
    , [RecTime]
)
          SELECT '21', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '22', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '23', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '24', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)
UNION ALL SELECT '25', DATEADD(day, (ABS(CHECKSUM(NEWID())) % 65530), 0)

INSERT INTO @Files (
      [ID]
    , [tblName]
    , [tblID]
    , [BinaryData]
)
          SELECT '1', 'Table1', '1', 0x010203040506
UNION ALL SELECT '2', 'Table1', '2', 0x010203040506
UNION ALL SELECT '3', 'Table1', '2', 0x010203040506
UNION ALL SELECT '4', 'Table1', '3', 0x010203040506
UNION ALL SELECT '5', 'Table1', '4', 0x010203040506
UNION ALL SELECT '6', 'Table1', '5', 0x010203040506
UNION ALL SELECT '7', 'Table1', '5', 0x010203040506

UNION ALL SELECT '8', 'Table2', '1', 0x010203040506
UNION ALL SELECT '9', 'Table2', '3', 0x010203040506
UNION ALL SELECT '10', 'Table2', '3', 0x010203040506
UNION ALL SELECT '11', 'Table2', '4', 0x010203040506
UNION ALL SELECT '12', 'Table2', '5', 0x010203040506
UNION ALL SELECT '13', 'Table2', '5', 0x010203040506
UNION ALL SELECT '14', 'Table2', '5', 0x010203040506

UNION ALL SELECT '15', 'Table3', '1', 0x010203040506
UNION ALL SELECT '16', 'Table3', '1', 0x010203040506
UNION ALL SELECT '17', 'Table3', '1', 0x010203040506
UNION ALL SELECT '18', 'Table3', '3', 0x010203040506
UNION ALL SELECT '19', 'Table3', '3', 0x010203040506
UNION ALL SELECT '20', 'Table3', '3', 0x010203040506
UNION ALL SELECT '21', 'Table3', '4', 0x010203040506

--SELECT * FROM @Table1
--SELECT * FROM @Table2
--SELECT * FROM @Table3

SELECT F.*, RecTime = 
      CASE tblName  
         WHEN 'Table1' THEN T1.RecTime
         WHEN 'Table2' THEN T2.RecTime
         WHEN 'Table3' THEN T3.RecTime
         ELSE 'UnKnown Table'  
      END 
FROM @Files F
LEFT JOIN @Table1 T1 ON F.tblID = T1.ID
LEFT JOIN @Table2 T2 ON F.tblID = T2.ID
LEFT JOIN @Table3 T3 ON F.tblID = T3.ID

View schema
Execution time: 0,02 sec, rows selected: 21, rows affected: 36, absolute service time: 0,16 sec