Utilizzo di IF EXISTS con un CTE

Da MSDN

Può essere riscritto in questo modo

WITH ADMISSION_OUTSIDE AS 
(   .....
.....
)
SELECT 'OK' WHERE EXISTS (SELECT * FROM ADMISSION_OUTSIDE)
UNION ALL
SELECT 'NOT OK' WHERE NOT EXISTS (SELECT * FROM ADMISSION_OUTSIDE)

Ecco una demo

;WITH CTE AS
(
SELECT 1 as a WHERE 1=0
)
SELECT 'OK' WHERE EXISTS (SELECT * FROM CTE)
UNION ALL
SELECT 'NOT OK' WHERE NOT EXISTS (SELECT * FROM CTE)

Risultato : NOT OK

;WITH CTE AS
(
SELECT 1 as a WHERE 1=1
)
SELECT 'OK' WHERE EXISTS (SELECT * FROM CTE)
UNION ALL
SELECT 'NOT OK' WHERE NOT EXISTS (SELECT * FROM CTE)

Risultato : OK