针对您提出的“function regexp_substr does not exist”问题,我将按照您给出的提示进行回答: 1. 确认regexp_substr函数的可用性 regexp_substr是一个在多个数据库系统中可用的函数,主要用于根据正则表达式提取子字符串。然而,并非所有数据库系统都内置了这个函数。它常见于Oracle、PostgreSQL(通过扩展或特定版本)等数...
REGEXP_SUBSTR(str,pattern,[position[,occurrence[,match_param[,subexpr]]]) Purpose REGEXP_SUBSTR() searches the str string for the substring that matches the regular expression specified by pattern. The function returns NULL if the substring does not exist. This function supports multi-byte char...
mysql> SHOW CREATE FUNCTION REGEXP_SUBSTR; ERROR 1305 (42000): FUNCTION REGEXP_SUBSTR does not exist # What about SHOW FUNCTION? mysql> SHOW FUNCTION STATUS LIKE '%REGEX%'; Empty set (0.00 sec) # Found in I_S.ROUTINES? mysql> SELECT * FROM INFORMATION_SCHEMA.ROUTINES -> WHERE ROUTINE...
没有任何问题。似乎您想要从同一个正则表达式中检查多个匹配项。在Postgres中，这样做的方法是在regex上...
mysql> SHOW CREATE FUNCTION REGEXP_SUBSTR; ERROR 1305 (42000): FUNCTION REGEXP_SUBSTR does not exist # What about SHOW FUNCTION? mysql> SHOW FUNCTION STATUS LIKE '%REGEX%'; Empty set (0.00 sec) # Found in I_S.ROUTINES? mysql> SELECT * FROM INFORMATION_SCHEMA.ROUTINES -> WHERE ROUTINE...