使用CASE
而不是IF
:
SELECT
FIRST_NAME,
LAST_NAME,
ULTIMATE_PARENT_NAME,
CASE WHEN LOCATION_ACCOUNT_ID IS NULL THEN 'Y' ELSE '' END AS IMPACT
FROM (
SELECT DISTINCT
A.FIRST_NAME,
A.LAST_NAME,
B.LOCATION_ACCOUNT_ID,
A.ULTIMATE_PARENT_NAME
FROM ACTIVE_ACCOUNTS A,
QL_ASSETS B
WHERE A.ACCOUNT_ID = B.LOCATION_ACCOUNT_ID(+)
您还应该使用LEFT JOIN语法,而不是旧的(+)语法(但在这种情况下,更多的是风格的选择 - 它不改变的结果):
SELECT
FIRST_NAME,
LAST_NAME,
ULTIMATE_PARENT_NAME,
CASE WHEN LOCATION_ACCOUNT_ID IS NULL THEN 'Y' ELSE '' END AS IMPACT
FROM (
SELECT DISTINCT
A.FIRST_NAME,
A.LAST_NAME,
B.LOCATION_ACCOUNT_ID,
A.ULTIMATE_PARENT_NAME
FROM ACTIVE_ACCOUNTS A
LEFT JOIN QL_ASSETS B
ON A.ACCOUNT_ID = B.LOCATION_ACCOUNT_ID
)
事实上,既然你是使用任何列不从B
在结果(只检查是否存在),你可以只使用EXISTS
:
SELECT
FIRST_NAME,
LAST_NAME,
ULTIMATE_PARENT_NAME,
CASE WHEN EXISTS(SELECT NULL
FROM QL_ASSETS
WHERE LOCATION_ACCOUNT_ID = A.ACCOUNT_ID)
THEN 'Y'
ELSE ''
END AS IMPACT
FROM ACTIVE_ACCOUNTS A
谢谢斯坦利! – StephenT