Question

文档说regexp_instr（）和〜是区分大小写的Posix评估函数和运算符。是否有不区分大小写的Posix语法，或者基于PCRE的函数或运算符

的插件

在Redshift查询中尝试过的PCRE示例由于POSIX＆＃39;而无法正常工作。

select 
  A.target
, B.pattern
, regexp_instr(A.target, B.pattern) as rx_instr_position
, A.target ~ B.pattern as tilde_operator
, regexp_instr(A.target
, 'm/'||B.pattern||'/i') as rx_instr_position_icase
from
(      select 'AbCdEfffghi' as target 
 union select 'Chocolate' as target 
 union select 'Cocoa Latte' as target 
 union select 'coca puffs, delivered late' as target
) A
,
(      select 'choc.*late' as pattern 
 union select 'coca.*late' as pattern 
 union select 'choc\w+late' as pattern
 union select 'choc\\w+late' as pattern
) B

Answer 1

回答你的问题：我所知道没有与Redshift兼容的语法或插件。如果您可以使用解决方法：我们最终在字符串周围使用lower()来匹配：

select
  A.target
, B.pattern
, regexp_instr(A.target, B.pattern) as rx_instr_position
, A.target ~ B.pattern as tilde_operator
, regexp_instr(A.target, 'm/'||B.pattern||'/i') as rx_instr_position_icase
, regexp_instr(lower(A.target), B.pattern) as rx_instr_position_icase_by_lower
from
(      select 'AbCdEfffghi' as target
 union select 'Chocolate' as target
 union select 'Cocoa Latte' as target
 union select 'coca puffs, delivered late' as target
) A
,
(      select 'choc.*late' as pattern 
 union select 'coca.*late' as pattern 
 union select 'choc\w+late' as pattern
 union select 'choc\\w+late' as pattern
) B

Answer 2

Redshift现在通过添加函数参数Amazon Redshift - REGEXP_INSTR

为不区分大小写的正则表达式标志提供了直接解决方案

使用提供的查询示例的语法为：

select
  A.target
, B.pattern
, regexp_instr(A.target, B.pattern) as rx_instr_position
, A.target ~ B.pattern as tilde_operator
, regexp_instr(A.target, B.pattern, 1, 1, 0, 'i') AS rx_instr_position_icase
from
(      select 'AbCdEfffghi' as target
 union select 'Chocolate' as target
 union select 'Cocoa Latte' as target
 union select 'coca puffs, delivered late' as target
) A
,
(      select 'choc.*late' as pattern 
 union select 'coca.*late' as pattern 
 union select 'choc\w+late' as pattern
 union select 'choc\\w+late' as pattern
) B

Answer 3

select 'HELLO' ~* 'el' = true

当前未记录（2020-11-05）

Redshift SQL可以执行不区分大小写的正则表达式求值吗？

3 个答案: