这是我的查询,我需要在没有NULL的条件下检查子查询列previousenddate。
SELECT pa.policy_id,
pa.person_id,
(
SELECT COUNT(pas.person_id)
FROM `package_assignments` pas
WHERE pas.person_id = pa.person_id
GROUP BY pas.person_id
) AS Member_Count,
pe.full_name,
pa.start_date,
pa.end_date,
(
SELECT p.end_date
FROM `package_assignments` p
WHERE p.person_id = pa.person_id
ORDER BY p.end_date DESC LIMIT 1,
1
) previousenddate
FROM `package_assignments` pa,
persons pe
WHERE end_date BETWEEN "2017-04-01"
AND "2017-04-30"
AND pa.person_id = pe.id
AND pa.rmhc_location = 5006
AND previousenddate > 1
我需要检查previousenddate列而不使用Null For Eg:其中previousenddate<> ' NULL'