mysql - 错误 : FULL JOIN is only supported with merge-joinable join conditions

Question

当我尝试使用内部连接连接表时..它返回数据..但是当我使用完全外部连接连接 4 个表时我说

ERROR: FULL JOIN is only supported with merge-joinable join conditions"

查询示例:

SELECT hr_employee.name,hr_movement.amount,hr_concept.name,hr_period.name
FROM hr_employee
FULL OUTER JOIN hr_movement
ON hr_employee.ad_client_id=hr_movement.ad_client_id
FULL OUTER JOIN hr_concept
ON hr_movement.ad_client_id=hr_employee.ad_client_id
FULL OUTER JOIN hr_period
ON hr_concept.ad_client_id=hr_employee.ad_client_id

Answer 1

SELECT hr_employee.name,hr_movement.amount,hr_concept.name,hr_period.name
FROM hr_employee
FULL OUTER JOIN hr_movement
ON hr_employee.ad_client_id=hr_movement.ad_client_id
FULL OUTER JOIN hr_concept
ON hr_movement.ad_client_id=hr_employee.ad_client_id /*<- here*/
FULL OUTER JOIN hr_period
ON hr_concept.ad_client_id=hr_employee.ad_client_id /*<- and here*/

您正在连接表，但不要在连接条件中使用这些表。除此之外，MySQL 不支持FULL OUTER JOINs。它们像在 this answer 中一样实现.