Oracle 整数判断

SELECT C_NUM,
CASE
WHEN C_NUM - TRUNC(C_NUM) = 0 THEN
'整数'
ELSE
'非整数'
END
FROM (SELECT 3.000 C_NUM
FROM DUAL
UNION ALL
SELECT 3.100
FROM DUAL
UNION ALL
SELECT 4.400
FROM DUAL
UNION ALL
SELECT 5.400
FROM DUAL
UNION ALL
SELECT 5.000 FROM DUAL)