我這樣寫(xiě)為什么結(jié)果不對(duì)?
找了半天,也不知道哪兒出錯(cuò)了,大牛們,幫我看看啊,主要是a.id=2時(shí),數(shù)據(jù)為空
select user_name,
?? ?replace(
?? ?substring(substring_index(mobile, ',', a.id),char_length(substring_index(mobile, ',', a.id-1)) + 1),',','') as mobile
from tb_sequence a
??? cross join (
?? ??? ?select
?? ??? ??? ?user_name,
??????????? concat(mobile,',') as mobile,
??????????? length(mobile) - length(replace(mobile,',', ''))+1 size
?? ??? ?from user1 b
??? ) b on a.id <= b.size;
2017-01-10
不清楚你的表結(jié)構(gòu)是什么,所以很難去說(shuō)哪里出錯(cuò)了。但是用數(shù)據(jù)庫(kù)最好還是少用函數(shù),這樣的話性能會(huì)大大的提高,盡量把函數(shù)的方法用代碼解決
2017-07-05
/* Navicat?MySQL?Data?Transfer Source?Server?????????:?127.0.0.1_3306 Source?Server?Version?:?50553 Source?Host???????????:?127.0.0.1:3306 Source?Database???????:?test Target?Server?Type????:?MYSQL Target?Server?Version?:?50553 File?Encoding?????????:?65001 Date:?2017-07-05?16:37:02 */ SET?FOREIGN_KEY_CHECKS=0; --?---------------------------- --?Table?structure?for?tb_sequence --?---------------------------- DROP?TABLE?IF?EXISTS?`tb_sequence`; CREATE?TABLE?`tb_sequence`?( ??`id`?int(11)?NOT?NULL?AUTO_INCREMENT, ??PRIMARY?KEY?(`id`) )?ENGINE=MyISAM?AUTO_INCREMENT=10?DEFAULT?CHARSET=utf8?COMMENT='排序表ID要大于分割的逗號(hào)'; --?---------------------------- --?Records?of?tb_sequence --?---------------------------- INSERT?INTO?`tb_sequence`?VALUES?('1'); INSERT?INTO?`tb_sequence`?VALUES?('2'); INSERT?INTO?`tb_sequence`?VALUES?('3'); INSERT?INTO?`tb_sequence`?VALUES?('4'); INSERT?INTO?`tb_sequence`?VALUES?('5'); INSERT?INTO?`tb_sequence`?VALUES?('6'); INSERT?INTO?`tb_sequence`?VALUES?('7'); INSERT?INTO?`tb_sequence`?VALUES?('8'); INSERT?INTO?`tb_sequence`?VALUES?('9'); --?---------------------------- --?Table?structure?for?user_kills --?---------------------------- DROP?TABLE?IF?EXISTS?`user_kills`; CREATE?TABLE?`user_kills`?( ??`id`?smallint(5)?unsigned?NOT?NULL?AUTO_INCREMENT, ??`user_id`?smallint(5)?unsigned?DEFAULT?NULL, ??`timestr`?timestamp?NOT?NULL?DEFAULT?CURRENT_TIMESTAMP, ??`kills`?smallint(5)?unsigned?DEFAULT?NULL, ??PRIMARY?KEY?(`id`) )?ENGINE=MyISAM?AUTO_INCREMENT=10?DEFAULT?CHARSET=utf8; --?---------------------------- --?Records?of?user_kills --?---------------------------- INSERT?INTO?`user_kills`?VALUES?('1',?'2',?'2013-01-10?00:00:00',?'10'); INSERT?INTO?`user_kills`?VALUES?('2',?'2',?'2013-02-01?00:00:00',?'2'); INSERT?INTO?`user_kills`?VALUES?('3',?'2',?'2013-02-05?00:00:00',?'12'); INSERT?INTO?`user_kills`?VALUES?('4',?'4',?'2013-01-10?00:00:00',?'3'); INSERT?INTO?`user_kills`?VALUES?('5',?'4',?'2013-02-11?00:00:00',?'5'); INSERT?INTO?`user_kills`?VALUES?('6',?'2',?'2013-02-06?00:00:00',?'1'); INSERT?INTO?`user_kills`?VALUES?('7',?'3',?'2013-01-11?00:00:00',?'20'); INSERT?INTO?`user_kills`?VALUES?('8',?'2',?'2013-02-12?00:00:00',?'10'); INSERT?INTO?`user_kills`?VALUES?('9',?'3',?'2013-02-07?00:00:00',?'17'); --?---------------------------- --?Table?structure?for?user1 --?---------------------------- DROP?TABLE?IF?EXISTS?`user1`; CREATE?TABLE?`user1`?( ??`id`?smallint(5)?unsigned?NOT?NULL?AUTO_INCREMENT, ??`user_name`?varchar(40)?DEFAULT?NULL, ??`over`?varchar(40)?DEFAULT?NULL, ??`mobile`?varchar(255)?NOT?NULL, ??PRIMARY?KEY?(`id`) )?ENGINE=MyISAM?AUTO_INCREMENT=5?DEFAULT?CHARSET=utf8; --?---------------------------- --?Records?of?user1 --?---------------------------- INSERT?INTO?`user1`?VALUES?('1',?'唐僧',?'旃檀功德佛',?'123456,456789,774411'); INSERT?INTO?`user1`?VALUES?('2',?'豬八戒',?'凈壇使者',?'987654,3216545,754123'); INSERT?INTO?`user1`?VALUES?('3',?'孫悟空',?'斗戰(zhàn)勝佛',?'123456789,654321,789'); INSERT?INTO?`user1`?VALUES?('4',?'沙僧',?'金身羅漢',?'789422,4456789,654321'); --?---------------------------- --?Table?structure?for?user2 --?---------------------------- DROP?TABLE?IF?EXISTS?`user2`; CREATE?TABLE?`user2`?( ??`id`?smallint(5)?unsigned?NOT?NULL?AUTO_INCREMENT, ??`user_name`?varchar(40)?DEFAULT?NULL, ??`over`?varchar(40)?DEFAULT?NULL, ??PRIMARY?KEY?(`id`) )?ENGINE=MyISAM?AUTO_INCREMENT=6?DEFAULT?CHARSET=utf8; --?---------------------------- --?Records?of?user2 --?---------------------------- INSERT?INTO?`user2`?VALUES?('1',?'孫悟空',?'成佛'); INSERT?INTO?`user2`?VALUES?('2',?'牛魔王',?'被降服'); INSERT?INTO?`user2`?VALUES?('3',?'蛟魔王',?'被降服'); INSERT?INTO?`user2`?VALUES?('4',?'鵬魔王',?'被降服'); INSERT?INTO?`user2`?VALUES?('5',?'獅駝王',?'被降服');sql語(yǔ)句是對(duì)的