我正在使用MySQL并且有两个单独的表，PRE_REGISTERED和REGISTERED，我想使用UNION查询它们以获得整个组合结果。我也使用限制分页。最后，我想使用SQL_CALC_FOUND_ROWS为分页获取总行数。但是，我的数据在PRE_REGISTERED上大约有160,000行。如果我UNION ALL尽管我将数据限制为每页10行，那么查询仍需要很长时间（大约6秒）。像这样的查询
SELECT (
SELECT R.id, R.first_name, R.last_name, R.status
FROM REGISTERED R
WHERE R.status = 2 LIMIT 0, 10)
UNION ALL
(SELECT PR.id, PR.first_name, PR.last_name, PR.status
FROM PRE_REGISTERED PR
WHERE PR.status = 3 LIMIT 0, 10)
as U ORDER BY id LIMIT 0, 10
然后我尝试将LIMIT放在每个子查询上，结果很迷人（大约0.5秒），但是分页变得搞砸了。
查询是这样的：
SELECT SQL_CALC_FOUND_ROWS U.*, S.name as spc_name, S.short_desc as
spc_short_desc, GROUP_CONCAT(DISTINCT(S2.designation) SEPARATOR ', ') as
spc_dsg, GROUP_CONCAT(DISTINCT(EM.designation) SEPARATOR ', ') as em_dsg,
GROUP_CONCAT(DISTINCT(EF.designation) SEPARATOR ', ') as ef_dsg FROM (
(
/** REGISTERED **/
SELECT D.id, D.doc_title, D.user_email, D.first_name, D.last_name,
D.gender, D.dob, D.rating, D.no_of_rating, D.photo_file,
D.verification_status, ((D.rating * 8) + D.no_of_rating) as rating_score,
GROUP_CONCAT(DISTINCT(PP.id) SEPARATOR '|') as pp_id,
GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id, PP.name)) SEPARATOR '|') as
pp_name, GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id, PP.address)) SEPARATOR
'|') as pp_address, GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id, PP.phone))
SEPARATOR '|') as pp_phone, GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id,
V.name)) SEPARATOR '|') as pp_vil, GROUP_CONCAT(DISTINCT(CONCAT_WS('#',
PP.id, SD.name)) SEPARATOR '|') as pp_sub_d,
GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id, C.name)) SEPARATOR '|') as
pp_city, GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id, P.name)) SEPARATOR '|')
as pp_province, GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id, PP.zipcode))
SEPARATOR '|') as pp_zip, GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id,
RDPP.is_primary)) SEPARATOR '|') as pp_is_primary,
GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id, PP.latitude)) SEPARATOR '|') as
pp_lat, GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id, PP.longitude)) SEPARATOR
'|') as pp_lng, GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id, PP.type))
SEPARATOR '|') as pp_type, GROUP_CONCAT(DISTINCT(CONCAT_WS('#', PP.id, (
6371 * acos( cos( radians(-6.2087634) ) * cos( radians( PP.latitude ) ) *
cos( radians( PP.longitude ) - radians(106.845599) ) + sin(
radians(-6.2087634) ) * sin( radians( PP.latitude ) ) ) ))) SEPARATOR '|')
as pp_distance, MIN(( 6371 * acos( cos( radians(-6.2087634) ) * cos(
radians( PP.latitude ) ) * cos( radians( PP.longitude ) -
radians(106.845599) ) + sin( radians(-6.2087634) ) * sin( radians(
PP.latitude ) ) ) )) as min_pp_distance,
GROUP_CONCAT(DISTINCT(CONCAT_WS('#', D.id, DPW.day, DPW.start_time))
SEPARATOR '|') as dpweek_stime , (SELECT comment FROM ref_doctor_review RDR
WHERE RDR.doctor_id = D.id ORDER BY RDR.date DESC LIMIT 1) as comment, 1 as
reg_status FROM doctor D LEFT JOIN ref_doctor_practice_place RDPP ON
RDPP.doctor_id = D.id LEFT JOIN practice_place PP ON RDPP.practice_place_id
= PP.id LEFT JOIN duty_period DPW ON RDPP.id = DPW.ref_doctor_pplace_id
INNER JOIN village V ON PP.village_id = V.id INNER JOIN sub_district SD ON
V.sub_district_id = SD.id INNER JOIN city C ON SD.city_id = C.id INNER JOIN
province P ON P.id = C.province_id LEFT JOIN city DC ON D.city_id = DC.id
INNER JOIN province DP ON DP.id = DC.province_id AND ( DP.name LIKE 'DKI
Jakarta%' OR DP.long_name LIKE 'DKI Jakarta%' ) WHERE D.active_form >= 5 AND
D.verification_status = 1 GROUP BY D.id )
在子查询中使用LIMIT还有什么方法可以获得总行吗？
我决定把整个查询，但它很长。我希望有人能发现错误并帮助我。我完全陷入了困境。
MY ACTUAL SQL QUERY
/** PRE REGISTERED **/
SELECT RD.id * -1 as id, RD.doc_title as doc_title, NULL as user_email,
RD.first_name, RD.last_name, RD.gender, 0 as dob, 0 as rating, 0 as
no_of_rating, null as photo_file, null as verification_status, 0 as
rating_score, PP.id as pp_id, CONCAT_WS('#', PP.id, PP.name) as pp_name,
CONCAT_WS('#', PP.id, PP.address) as pp_address, CONCAT_WS('#', PP.id,
PP.phone) as pp_phone, CONCAT_WS('#', PP.id, V.name)as pp_vil,
CONCAT_WS('#', PP.id, SD.name) as pp_sub_d, CONCAT_WS('#', PP.id, C.name) as
pp_city, CONCAT_WS('#', PP.id, P.name) as pp_province, CONCAT_WS('#', PP.id,
PP.zipcode) as pp_zip, 1 pp_is_primary, CONCAT_WS('#', PP.id, PP.latitude)
as pp_lat, CONCAT_WS('#', PP.id, PP.longitude) as pp_lng, CONCAT_WS('#',
PP.id, PP.type) as pp_type, CONCAT_WS('#', PP.id, IF(PP.latitude <> 0 AND
PP.longitude <> 0, ( 6371 * acos( cos( radians(-6.2087634) ) * cos( radians(
PP.latitude ) ) * cos( radians( PP.longitude ) - radians(106.845599) ) +
sin( radians(-6.2087634) ) * sin( radians( PP.latitude ) ) ) ), 0)) as
pp_distance, IF(PP.latitude <> 0 AND PP.longitude <> 0, ( 6371 * acos( cos(
radians(-6.2087634) ) * cos( radians( PP.latitude ) ) * cos( radians(
PP.longitude ) - radians(106.845599) ) + sin( radians(-6.2087634) ) * sin(
radians( PP.latitude ) ) ) ) , 9999999) as min_pp_distance, null as dp_week,
null as comment, RD.status as reg_status FROM register_doctor RD LEFT JOIN
ref_doctor_practice_place RDPP ON RDPP.doctor_id = RD.id * -1 LEFT JOIN
practice_place PP ON PP.id = RDPP.practice_place_id LEFT JOIN village V ON
V.id = PP.village_id LEFT JOIN sub_district SD ON SD.id = PP.sub_district_id
LEFT JOIN city C ON C.id = SD.city_id INNER JOIN province P ON P.id =
PP.province_id LEFT JOIN city RDC ON RDC.id = RD.city_id INNER JOIN province
RDP ON RDP.id = RD.province_id AND ( RDP.name LIKE 'DKI Jakarta%' OR
RDP.long_name LIKE 'DKI Jakarta%' ) WHERE RD.status = 2 GROUP BY RD.id )
) AS U INNER JOIN ref_doctor_specialty RDS ON RDS.doctor_id = U.id AND
RDS.is_primary = 1 INNER JOIN specialty S ON S.id = RDS.specialty_id INNER
JOIN ref_doctor_specialty RDS2 ON RDS2.doctor_id = U.id INNER JOIN specialty
S2 ON S2.id = RDS2.specialty_id LEFT JOIN ref_doctor_education RDE ON
RDE.doctor_id = U.id LEFT JOIN edu_magister EM ON RDE.type = 4 AND EM.id =
RDE.ref_edu_id LEFT JOIN edu_fellowship EF ON RDE.type = 5 AND EF.id =
RDE.ref_edu_id WHERE U.min_pp_distance < 100 OR U.min_pp_distance = 9999999
GROUP BY U.id ORDER BY U.reg_status ASC, U.min_pp_distance ASC, RAND() LIMIT
0,10
UNION ALL（
CREATE TABLE `doctor` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`doc_title` varchar(15) DEFAULT NULL,
`user_email` varchar(50) NOT NULL,
`first_name` varchar(35) NOT NULL,
`last_name` varchar(35) DEFAULT NULL,
`gender` int(11) NOT NULL DEFAULT '0',
`dob` bigint(11) NOT NULL DEFAULT '0',
`rating` float NOT NULL DEFAULT '0',
`no_of_rating` int(11) NOT NULL DEFAULT '0',
`statement` text,
`password` char(64) NOT NULL,
`city_id` int(11) NOT NULL,
`active_form` int(11) NOT NULL DEFAULT '0',
`photo_file` varchar(40) NOT NULL,
`str_number` char(6) DEFAULT NULL,
`verify_file` varchar(40) DEFAULT NULL,
`verification_status` int(11) NOT NULL COMMENT '0 = Not verified, 1 = Verified, 2 = Pending Verification',
`reg_id` int(11) NOT NULL,
`reg_timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
KEY `city_id` (`city_id`),
KEY `verification_status` (`verification_status`),
KEY `active_form` (`active_form`),
CONSTRAINT `doctor_ibfk_1` FOREIGN KEY (`city_id`) REFERENCES `city` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=261 DEFAULT CHARSET=latin1
CREATE TABLE `register_doctor` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`doc_title` int(11) NOT NULL,
`first_name` varchar(35) NOT NULL,
`last_name` varchar(35) DEFAULT NULL,
`gender` int(11) NOT NULL,
`city_id` int(11) NOT NULL,
`province_id` int(11) NOT NULL,
`status` int(11) NOT NULL COMMENT '0 = Pending; 1 = Verified, 2 = Not Reg Yet, 3 = Pending Approval',
`str_number` char(6) DEFAULT NULL,
`editted_by` int(11) DEFAULT NULL,
`editted_date` bigint(20) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `city_id` (`city_id`),
KEY `province_id` (`province_id`),
KEY `status` (`status`),
CONSTRAINT `register_doctor_ibfk_1` FOREIGN KEY (`city_id`) REFERENCES `city` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=179327 DEFAULT CHARSET=latin1
CREATE TABLE `practice_place` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(75) NOT NULL,
`statement` text,
`address` varchar(200) NOT NULL,
`phone` varchar(15) NOT NULL,
`fax` varchar(15) NOT NULL,
`email` varchar(50) NOT NULL,
`village_id` varchar(50) NOT NULL,
`sub_district_id` varchar(50) NOT NULL,
`province_id` varchar(50) NOT NULL,
`zipcode` varchar(10) NOT NULL,
`website` varchar(50) NOT NULL,
`latitude` double NOT NULL,
`longitude` double NOT NULL,
`type` int(11) NOT NULL,
`managed_by` int(11) DEFAULT '0',
`doctor_group_id` int(11) NOT NULL,
`category` varchar(50) NOT NULL,
`photo_file` char(36) NOT NULL,
`is_branch` int(11) NOT NULL,
`parent_id` int(11) NOT NULL,
`editted_by` int(11) NOT NULL,
`editted_date` bigint(20) NOT NULL,
`status` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `village_id` (`village_id`),
KEY `doctor_group_id` (`doctor_group_id`),
KEY `province_id` (`province_id`),
KEY `type` (`type`),
KEY `parent_id` (`parent_id`),
KEY `longitude` (`longitude`),
KEY `latitude` (`latitude`)
) ENGINE=InnoDB AUTO_INCREMENT=25554 DEFAULT CHARSET=latin1
CREATE TABLE `ref_doctor_practice_place` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`doctor_id` int(11) NOT NULL,
`practice_place_id` int(11) NOT NULL,
`is_primary` int(11) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `doctor_id_2` (`doctor_id`,`practice_place_id`),
KEY `doctor_id` (`doctor_id`),
KEY `practice_place_id` (`practice_place_id`),
CONSTRAINT `ref_doctor_practice_place_ibfk_1` FOREIGN KEY (`practice_place_id`) REFERENCES `practice_place` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=38772 DEFAULT CHARSET=latin1
CREATE TABLE `ref_doctor_specialty` (
`doctor_id` int(11) NOT NULL,
`specialty_id` int(11) NOT NULL,
`is_primary` int(11) NOT NULL DEFAULT '0',
PRIMARY KEY (`doctor_id`,`specialty_id`),
UNIQUE KEY `doctor_id_2` (`doctor_id`,`specialty_id`),
KEY `doctor_id` (`doctor_id`),
KEY `specialty_id` (`specialty_id`),
KEY `is_primary` (`is_primary`),
CONSTRAINT `ref_doctor_specialty_ibfk_1` FOREIGN KEY (`specialty_id`) REFERENCES `specialty` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
CREATE TABLE `ref_doctor_education` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`doctor_id` int(11) NOT NULL,
`type` int(11) NOT NULL,
`institution` varchar(150) NOT NULL,
`ref_edu_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `doctor_id` (`doctor_id`),
KEY `ref_edu_id` (`ref_edu_id`),
KEY `type` (`type`)
) ENGINE=InnoDB AUTO_INCREMENT=187556 DEFAULT CHARSET=latin1
CREATE TABLE `edu_fellowship` (
`id` int(11) NOT NULL,
`name` varchar(150) NOT NULL,
`designation` varchar(10) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
CREATE TABLE `edu_magister` (
`id` int(11) NOT NULL,
`name` varchar(55) NOT NULL,
`designation` varchar(15) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
CREATE TABLE `village` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(35) NOT NULL,
`sub_district_id` int(11) NOT NULL,
`zipcode` char(5) NOT NULL,
PRIMARY KEY (`id`),
KEY `sub_district_id` (`sub_district_id`),
CONSTRAINT `village_ibfk_1` FOREIGN KEY (`sub_district_id`) REFERENCES `sub_district` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=81360 DEFAULT CHARSET=latin1
CREATE TABLE `sub_district` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(35) NOT NULL,
`city_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `city_id` (`city_id`),
CONSTRAINT `sub_district_ibfk_1` FOREIGN KEY (`city_id`) REFERENCES `city` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=7000 DEFAULT CHARSET=latin1
CREATE TABLE `province` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(40) NOT NULL,
`long_name` varchar(40) NOT NULL,
`abbreviation` char(2) NOT NULL,
`area_group` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=47 DEFAULT CHARSET=latin1
CREATE TABLE `duty_period` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`day` int(11) NOT NULL,
`start_time` bigint(11) NOT NULL,
`end_time` bigint(11) NOT NULL,
`ref_doctor_pplace_id` int(11) NOT NULL DEFAULT '0',
PRIMARY KEY (`id`),
UNIQUE KEY `day` (`day`,`start_time`,`ref_doctor_pplace_id`),
KEY `ref_doctor_pplace_id` (`ref_doctor_pplace_id`),
CONSTRAINT `duty_period_ibfk_1` FOREIGN KEY (`ref_doctor_pplace_id`) REFERENCES `ref_doctor_practice_place` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=766 DEFAULT CHARSET=latin1
CREATE TABLE `ref_doctor_review` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`date` bigint(20) NOT NULL,
`doctor_id` int(11) NOT NULL,
`helpfulness_rating` double NOT NULL,
`punctuality_rating` double NOT NULL,
`knowledge_rating` double NOT NULL,
`staff_rating` double NOT NULL,
`user_id` int(11) NOT NULL,
`comment` text,
`patient_id` int(11) NOT NULL DEFAULT '0',
`is_anonymous` int(11) NOT NULL DEFAULT '0',
`date_visit` bigint(20) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `doctor_id` (`doctor_id`),
KEY `patient_id` (`user_id`),
CONSTRAINT `ref_doctor_review_ibfk_1` FOREIGN KEY (`doctor_id`) REFERENCES `doctor` (`id`),
CONSTRAINT `ref_doctor_review_ibfk_2` FOREIGN KEY (`user_id`) REFERENCES `user` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1
CREATE TABLE `city` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(40) NOT NULL,
`city_type` int(11) NOT NULL,
`province_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `state_id` (`province_id`),
CONSTRAINT `city_ibfk_1` FOREIGN KEY (`province_id`) REFERENCES `province` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=515 DEFAULT CHARSET=latin1
CREATE TABLE `specialty` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(80) NOT NULL,
`short_desc` varchar(50) NOT NULL,
`name_en` varchar(80) NOT NULL,
`short_desc_en` varchar(50) NOT NULL,
`designation` varchar(15) NOT NULL,
`is_popular` int(11) NOT NULL DEFAULT '0',
`spc_group` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `spc_group` (`spc_group`)
) ENGINE=InnoDB AUTO_INCREMENT=307 DEFAULT CHARSET=latin1
PS。我已经为索引添加了几乎所有必要的列。
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
1 PRIMARY RDS ALL PRIMARY,doctor_id_2,doctor_id,specialty_id 30 Using where; Using temporary; Using filesort
1 PRIMARY S eq_ref PRIMARY PRIMARY 4 lokadok.RDS.specialty_id 1
1 PRIMARY <derived2> ref <auto_key0> <auto_key0> 8 lokadok.RDS.doctor_id 76 Using index condition
1 PRIMARY RDS2 ref PRIMARY,doctor_id_2,doctor_id,specialty_id PRIMARY 4 U.id 1 Using where; Using index
1 PRIMARY S2 eq_ref PRIMARY PRIMARY 4 lokadok.RDS2.specialty_id 1
1 PRIMARY RDE ref doctor_id doctor_id 4 U.id 1 Using where
1 PRIMARY EM eq_ref PRIMARY PRIMARY 4 lokadok.RDE.ref_edu_id 1 Using where
1 PRIMARY EF eq_ref PRIMARY PRIMARY 4 lokadok.RDE.ref_edu_id 1 Using where
2 DERIVED D index PRIMARY,city_id,full_name PRIMARY 4 37 Using where
2 DERIVED DC eq_ref PRIMARY,state_id PRIMARY 4 lokadok.D.city_id 1 Using where
2 DERIVED DP eq_ref PRIMARY PRIMARY 4 lokadok.DC.province_id 1 Using where
2 DERIVED RDPP ref practice_place_id,doctor_id doctor_id 4 lokadok.D.id 1
2 DERIVED DPW ref ref_doctor_pplace_id ref_doctor_pplace_id 4 lokadok.RDPP.id 1
2 DERIVED PP eq_ref PRIMARY,village_id PRIMARY 4 lokadok.RDPP.practice_place_id 1 Using where
2 DERIVED V eq_ref PRIMARY,sub_district_id PRIMARY 4 lokadok.PP.village_id 1 Using where
2 DERIVED SD eq_ref PRIMARY,city_id PRIMARY 4 lokadok.V.sub_district_id 1
2 DERIVED C eq_ref PRIMARY,state_id PRIMARY 4 lokadok.SD.city_id 1
2 DERIVED P eq_ref PRIMARY PRIMARY 4 lokadok.C.province_id 1
3 DEPENDENT SUBQUERY RDR ref doctor_id doctor_id 4 func 1 Using where; Using filesort
4 UNION RDP ALL PRIMARY 36 Using where; Using temporary; Using filesort
4 UNION RD ref PRIMARY,city_id,province_id,full_name province_id 4 lokadok.RDP.id 210 Using where
4 UNION RDC eq_ref PRIMARY PRIMARY 4 lokadok.RD.city_id 1 Using index
4 UNION RDPP ref practice_place_id,doctor_id doctor_id 4 func 1 Using index condition
4 UNION PP eq_ref PRIMARY PRIMARY 4 lokadok.RDPP.practice_place_id 1 Using where
4 UNION P eq_ref PRIMARY PRIMARY 4 lokadok.PP.province_id 1 Using where
4 UNION V eq_ref PRIMARY PRIMARY 4 lokadok.PP.village_id 1 Using where
4 UNION SD eq_ref PRIMARY PRIMARY 4 lokadok.PP.sub_district_id 1 Using where
4 UNION C eq_ref PRIMARY PRIMARY 4 lokadok.SD.city_id 1
UNION RESULT <union2,4> ALL Using temporary
这就是全部！架构... pheww。帮帮我Drew。 ：）
EXPLAIN表
+------------+----------------------------+------------+-----------------------+--------------+-----------------------+------------+-------------+-------------+-------------+----------+------------+
| table_rows | table_name | non_unique | index_name | seq_in_index | column_name | collation | cardinality | sub_part | packed | nullable | index_type |
+------------+----------------------------+------------+-----------------------+--------------+-----------------------+------------+-------------+-------------+-------------+----------+------------+
"514" | "city" | "0" | "PRIMARY" | "1" | "id" | "A" | "514" | NULL | NULL | | "BTREE"
"514" | "city" | "1" | "state_id" | "1" | "province_id" | "A" | "73" | NULL | NULL | | "BTREE"
"259" | "doctor" | "1" | "active_form" | "1" | "active_form" | "A" | "12" | NULL | NULL | | "BTREE"
"259" | "doctor" | "1" | "city_id" | "1" | "city_id" | "A" | "259" | NULL | NULL | | "BTREE"
"259" | "doctor" | "0" | "PRIMARY" | "1" | "id" | "A" | "259" | NULL | NULL | | "BTREE"
"259" | "doctor" | "1" | "verification_status" | "1" | "verification_status" | "A" | "6" | NULL | NULL | | "BTREE"
"690" | "duty_period" | "0" | "day" | "2" | "start_time" | "A" | "345" | NULL | NULL | | "BTREE"
"690" | "duty_period" | "0" | "day" | "1" | "day" | "A" | "14" | NULL | NULL | | "BTREE"
"690" | "duty_period" | "0" | "day" | "3" | "ref_doctor_pplace_id"| "A" | "690" | NULL | NULL | | "BTREE"
"690" | "duty_period" | "0" | "PRIMARY" | "1" | "id" | "A" | "690" | NULL | NULL | | "BTREE"
"690" | "duty_period" | "1" | "ref_doctor_pplace_id"| "1" | "ref_doctor_pplace_id"| "A" | "345" | NULL | NULL | | "BTREE"
"15" | "edu_fellowship" | "0" | "PRIMARY" | "1" | "id" | "A" | "15" | NULL | NULL | | "BTREE"
"19" | "edu_magister" | "0" | "PRIMARY" | "1" | "id" | "A" | "19" | NULL | NULL | | "BTREE"
"5766" | "practice_place" | "1" | "doctor_group_id" | "1" | "doctor_group_id" | "A" | "411" | NULL | NULL | | "BTREE"
"5766" | "practice_place" | "1" | "latitude" | "1" | "latitude" | "A" | "5766" | NULL | NULL | | "BTREE"
"5766" | "practice_place" | "1" | "longitude" | "1" | "longitude" | "A" | "5766" | NULL | NULL | | "BTREE"
"5766" | "practice_place" | "1" | "parent_id" | "1" | "parent_id" | "A" | "5766" | NULL | NULL | | "BTREE"
"5766" | "practice_place" | "0" | "PRIMARY" | "1" | "id" | "A" | "5766" | NULL | NULL | | "BTREE"
"5766" | "practice_place" | "1" | "province_id" | "1" | "province_id" | "A" | "74" | NULL | NULL | | "BTREE"
"5766" | "practice_place" | "1" | "type" | "1" | "type" | "A" | "4" | NULL | NULL | | "BTREE"
"5766" | "practice_place" | "1" | "village_id" | "1" | "village_id" | "A" | "5766" | NULL | NULL | | "BTREE"
"36" | "province" | "0" | "PRIMARY" | "1" | "id" | "A" | "36" | NULL | NULL | | "BTREE"
"160406" | "ref_doctor_education" | "1" | "doctor_id" | "1" | "doctor_id" | "A" | "160406" | NULL | NULL | | "BTREE"
"160406" | "ref_doctor_education" | "0" | "PRIMARY" | "1" | "id" | "A" | "160406" | NULL | NULL | | "BTREE"
"160406" | "ref_doctor_education" | "1" | "ref_edu_id" | "1" | "ref_edu_id" | "A" | "128" | NULL | NULL | | "BTREE"
"160406" | "ref_doctor_education" | "1" | "type" | "1" | "type" | "A" | "8" | NULL | NULL | | "BTREE"
"15871" | "ref_doctor_practice_place"| "1" | "doctor_id" | "1" | "doctor_id" | "A" | "15871" | NULL | NULL | | "BTREE"
"15871" | "ref_doctor_practice_place"| "0" | "doctor_id_2" | "2" | "practice_place_id" | "A" | "15871" | NULL | NULL | | "BTREE"
"15871" | "ref_doctor_practice_place"| "0" | "doctor_id_2" | "1" | "doctor_id" | "A" | "15871" | NULL | NULL | | "BTREE"
"15871" | "ref_doctor_practice_place"| "1" | "practice_place_id" | "1" | "practice_place_id" | "A" | "3174" | NULL | NULL | | "BTREE"
"15871" | "ref_doctor_practice_place"| "0" | "PRIMARY" | "1" | "id" | "A" | "15871" | NULL | NULL | | "BTREE"
"2" | "ref_doctor_review" | "1" | "doctor_id" | "1" | "doctor_id" | "A" | "2" | NULL | NULL | | "BTREE"
"2" | "ref_doctor_review" | "1" | "patient_id" | "1" | "user_id" | "A" | "2" | NULL | NULL | | "BTREE"
"2" | "ref_doctor_review" | "0" | "PRIMARY" | "1" | "id" | "A" | "2" | NULL | NULL | | "BTREE"
"166830" | "ref_doctor_specialty" | "1" | "is_primary" | "1" | "is_primary" | "A" | "2" | NULL | NULL | | "BTREE"
"166830" | "ref_doctor_specialty" | "0" | "PRIMARY" | "2" | "specialty_id" | "A" | "166830" | NULL | NULL | | "BTREE"
"166830" | "ref_doctor_specialty" | "0" | "PRIMARY" | "1" | "doctor_id" | "A" | "166830" | NULL | NULL | | "BTREE"
"166830" | "ref_doctor_specialty" | "1" | "specialty_id" | "1" | "specialty_id" | "A" | "166" | NULL | NULL | | "BTREE"
"165958" | "register_doctor" | "1" | "city_id" | "1" | "city_id" | "A" | "1152" | NULL | NULL | | "BTREE"
"165958" | "register_doctor" | "0" | "PRIMARY" | "1" | "id" | "A" | "165958" | NULL | NULL | | "BTREE"
"165958" | "register_doctor" | "1" | "province_id" | "1" | "province_id" | "A" | "66" | NULL | NULL | | "BTREE"
"165958" | "register_doctor" | "1" | "status" | "1" | "status" | "A" | "4" | NULL | NULL | | "BTREE"
"101" | "specialty" | "0" | "PRIMARY" | "1" | "id" | "A" | "101" | NULL | NULL | | "BTREE"
"101" | "specialty" | "1" | "spc_group" | "1" | "spc_group" | "A" | "16" | NULL | NULL | | "BTREE"
"6999" | "sub_district" | "1" | "city_id" | "1" | "city_id" | "A" | "1166" | NULL | NULL | | "BTREE"
"6999" | "sub_district" | "0" | "PRIMARY" | "1" | "id" | "A" | "6999" | NULL | NULL | | "BTREE"
"80700" | "village" | "0" | "PRIMARY" | "1" | "id" | "A" | "80700" | NULL | NULL | | "BTREE"
"80700" | "village" | "1" | "sub_district_id" | "1" | "sub_district_id" | "A" | "13450" | NULL | NULL | | "BTREE"
统计结果：
output.setText(new StringBuilder().append(output.getText()).append(output.getResources().getString(R.string.newl2)).append(input.getText()));
答案 0 :(得分：0)
将OFFSET和LIMIT与UNION一起使用时，模式如下：
( SELECT ...
ORDER BY x -- required
LIMIT 130 -- outer OFFSET + LIMIT
) UNION ALL -- DISTINCT might work, too
( SELECT ...
ORDER BY x -- required
LIMIT 130 -- outer OFFSET + LIMIT
)
ORDER BY x -- again
LIMIT 120, 10 -- outer OFFSET and LIMIT
如果其中一个子查询中的所有（或只是一些）具有所需的行，那么120 + 10就足够了。
在任何地方都需要相同的ORDER BY，以便您选择正确的行。
与此同时，我不相信SQL_CALC_FOUND_ROWS给你正确答案。请参阅http://dev.mysql.com/doc/refman/5.6/en/information-functions.html并搜索“union”。此外，5.7.5修复了“带有SQL_CALC_FOUND_ROWS的UNION ALL查询和带有一个查询块的偏移量的LIMIT报告的行数不正确。”（＃Bug＃17833261）“
<强>附加物
将SQL_CALC_FOUND_ROWS添加到第一个SELECT，使用ALL。看看FOUND_ROWS()是否为您提供了正确的答案。如果您无法使用ALL，或LIMITs搞砸了CALC，那么我建议您在构建网页的同时无法获得答案。
如果没有ORDER BY RAND()以外的其他原因，您的查询必须查看所有数据。也就是说，即使某些索引可以加快速度，它们也不会使大量数据的获取短路。
答案 1 :(得分：0)
我会运行两个查询，一个带有count(*)且没有限制，另一个没有子选择而没有SQL_CALC_FOUND_ROWS。我不得不分批查询大约90k行，也知道总数，这就是我最终做的事情。
计数：
SELECT count(*) from (
(SELECT R.id, R.first_name, R.last_name, R.status
FROM REGISTERED R
WHERE R.status = 2)
UNION ALL
(SELECT PR.id, PR.first_name, PR.last_name, PR.status
FROM PRE_REGISTERED PR
WHERE PR.status = 3)) t;
实际数据：
(SELECT R.id, R.first_name, R.last_name, R.status
FROM REGISTERED R
WHERE R.status = 2)
UNION ALL
(SELECT PR.id, PR.first_name, PR.last_name, PR.status
FROM PRE_REGISTERED PR
WHERE PR.status = 3)
ORDER BY id LIMIT 0, 10
您还可以将其细分为3个查询，2个计数和1个数据，并将这两个计数加在一起。
答案 2 :(得分：0)
我想我找到了缓慢的因素。正是这部分使得整个查询变得缓慢。这个变量是一个别名，它是一个公式。
ORDER BY .... U.min_pp_distance
虽然我没有找到工作，但这证实了这个问题： MySQL-Performance when ordering on calculated column