SELECT a.[IdForcedAppointmentType],
  a.[ForcedAppointmentTypeTitle],
  b.[type],
  b.[allow]
FROM [calendars].[dbo].[ForcedAppointmentTypes] AS a 
 LEFT OUTER JOIN [calendars].[dbo].[Preference_exchange] AS b 
 ON a.[IdForcedAppointmentType] = b.[type] AND b.[uid] = ''

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