jquery - MYSQL WHERE EXISTS 执行时间过长

Question

我在MYSQL查询中使用WHERE EXISTS，但执行时间太长。你们能告诉我如何加快此查询的速度或建议我任何替代查询吗？

这是我的查询

SELECT a.property_id, count( a.booking_id ) AS total_bookings, group_concat( concat( date_format( a.check_in, '%m/%d/%Y' ) , '  To  ', date_format( a.check_out, '%m/%d/%Y' ) , '  ', '(', (

CASE a.book_status
WHEN 1
THEN 'Pending'
WHEN 3
THEN 'Confirm'
END
), ')', '  |  
<a href=\'manage_booking.php?action=ed&id=', a.booking_id, '\' target=_blank class=linkun >View Detail</a>', '<br>' ) ) AS dates
FROM apl_property_booking AS a
WHERE EXISTS (

SELECT booking_id
FROM apl_property_booking AS b
WHERE b.booking_id != a.booking_id
AND b.property_id = a.property_id
AND (
b.check_in < a.check_out
AND a.check_in < b.check_out
)
AND b.book_status
IN ( 1, 3 )
AND (
'2015-04-01' <= date_add( b.check_out, INTERVAL -1
DAY )
AND '2015-04-27' >= date_add( b.check_in, INTERVAL +1
DAY )
)
)
AND a.book_status
IN ( 1, 3 )
AND (
'2015-04-01' <= date_add( a.check_out, INTERVAL -1
DAY )
AND '2015-04-27' >= date_add( a.check_in, INTERVAL +1
DAY )
)
GROUP BY a.property_id
ORDER BY a.check_in DESC
LIMIT 0 , 30

Answer 1

我通过删除 MYSQL WHERE EXISTS 并替换为 LEFT JOIN 解决了这个问题。 使用 WHERE EXISTS 的查询执行时间为“37.4117 秒”，而使用 LEFT JOIN 的查询执行时间为“0.0097 秒”

这是我的新查询

SELECT a.property_id, count( a.booking_id ) AS total_bookings, group_concat( concat( date_format( a.check_in, '%m/%d/%Y' ) , '  To  ', date_format( a.check_out, '%m/%d/%Y' ) , '  ', '(', (

CASE a.book_status
WHEN 1
THEN 'Pending'
WHEN 3
THEN 'Confirm'
END
), ')', '  |  
<a href=\'manage_booking.php?action=ed&id=', a.booking_id, '\' target=_blank class=linkun >View Detail</a>', '<br>' ) ) AS dates
FROM apl_property_booking AS a
LEFT JOIN apl_property_booking AS b ON b.property_id = a.property_id
WHERE 
b.booking_id != a.booking_id AND 
(b.check_in < a.check_out
AND a.check_in < b.check_out
)
AND b.book_status
IN ( 1, 3 )
AND (
'2015-04-01' <= date_add( b.check_out, INTERVAL -1
DAY )
AND '2015-04-27' >= date_add( b.check_in, INTERVAL +1
DAY )
)
AND a.book_status
IN ( 1, 3 )
AND (
'2015-04-01' <= date_add( a.check_out, INTERVAL -1
DAY )
AND '2015-04-27' >= date_add( a.check_in, INTERVAL +1
DAY )
)
GROUP BY a.property_id
ORDER BY a.check_in DESC
LIMIT 0 , 30