mysql-炸裂函数的实现
标签：index 函数 http img replace ima sql sub sel
mysql-炸裂函数的实现
substring_index(substring_index(a.chain,‘_‘,b.help_topic_id + 1 ), ‘_‘ ,- 1 ) AS ID
FROM
(select ‘1_11_1223_1242‘ as chain) a
JOIN mysql.help_topic b ON b.help_topic_id <
(length(a.chain) - length( replace(a.chain, ‘_‘, ‘‘) ) + 1)