我正在尝试优化以下mysql查询。它运行约2.5秒。我已经阅读了复合索引，但希望有人能帮助我了解您如何使用包含多个联接，许多条件（包括日期范围），分组依据和排序依据的查询对复合索引进行排序计算值。我是否缺少有用的复合索引？我应该从这些表中提取数据有更有效的方法吗？任何帮助都非常感谢！
SELECT
branch.name AS branch,
SUM(appointment.status = 'completed') AS `Completed`,
SUM(appointment.status = 'cancelled') AS `Cancelled`,
SUM(appointment.status = 'not completed') AS `Not Completed`,
SUM(appointment.status != 'rescheduled') AS `Total`
FROM rep
JOIN customer ON rep.id = customer.rep_id
JOIN office ON rep.office_id = office.id
JOIN appointment ON customer.id = appointment.customer_id
JOIN branch ON office.branch_id = branch.id
WHERE rep.active= 1
AND rep.group IN (1,2,3)
AND rep.deleted = 0
AND customer.saved = 0
AND (customer.rep_id != appointment.closed_by OR appointment.closed_by IS NULL)
AND customer.rep_id != 0
AND customer.deleted = 0
AND office.visible = 1
AND office.deleted = 0
AND appointment.date >= '2016-12-01'
AND appointment.date < '2017-11-30'
AND appointment.current = 1
GROUP BY branch.id
ORDER BY Completed
这是EXPLAIN输出：
id: 1
select_type: simple
table: office
type: ref
possible_keys: PRIMARY, deleted_branchID_name, deleted_visible
key: deleted_visible
key_len: 5
ref: const,const
rows: 73
Extra: Using index condition; Using temporary; Using filesort
id: 1
select_type: simple
table: branch
type: eq_ref
possible_keys: PRIMARY
key: PRIMARY
key_len: 4
ref: office.branch_id
rows: 1
Extra: NULL
id: 1
select_type: simple
table: rep
type: ref
possible_keys: PRIMARY, group_id, office_id, active_deleted
key: office_id
key_len: 5
ref: office.id
rows: 57
Extra: Using index condition; Using where
id: 1
select_type: simple
table: customer
type: ref
possible_keys: PRIMARY, rep_id
key: rep_id
key_len: 4
ref: rep.id
rows: 61
Extra: Using where
id: 1
select_type: simple
table: appointment
type: ref
possible_keys: date, customer_id, closedByID_date, isCurrent_date
key: customer_id
key_len: 4
ref: customer.id
rows: 1
Extra: Using where
最佳答案
一条建议
删除条件上无用的（）
LEFT JOIN customer ON rep.id = customer.rep_id
LEFT JOIN office ON rep.office_id = office.id
LEFT JOIN appointment ON customer.id = appointment.customer_id
LEFT JOIN branch ON office.branch_id = branch.id
关于mysql - 复合索引顺序MySQL查询，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/44713123/