符〜<〜Postgres里

Question

^{（本this question一部分，但它是有点文不对题，所以我决定把它自身的问题。）}

我找不到什么操作~<~是。 Postgres手册只提及~和类似的运算符here，但没有符号~<~。

当PSQL控制台摆弄，我发现，这些命令给了相同的结果：

SELECT * FROM test ORDER BY name USING ~<~; 
SELECT * FROM test ORDER BY name COLLATE "C"; 

而且这些给出了相反的顺序：

SELECT * FROM test ORDER BY name USING ~>~; 
SELECT * FROM test ORDER BY name COLLATE "C" DESC; 

而且在波浪运营商的一些信息：

\do ~*~ 
            List of operators 
    Schema | Name | Left arg type | Right arg type | Result type |  Description  
------------+------+---------------+----------------+-------------+------------------------- 
pg_catalog | ~<=~ | character  | character  | boolean  | less than or equal 
pg_catalog | ~<=~ | text   | text   | boolean  | less than or equal 
pg_catalog | ~<~ | character  | character  | boolean  | less than 
pg_catalog | ~<~ | text   | text   | boolean  | less than 
pg_catalog | ~>=~ | character  | character  | boolean  | greater than or equal 
pg_catalog | ~>=~ | text   | text   | boolean  | greater than or equal 
pg_catalog | ~>~ | character  | character  | boolean  | greater than 
pg_catalog | ~>~ | text   | text   | boolean  | greater than 
pg_catalog | ~~ | bytea   | bytea   | boolean  | matches LIKE expression 
pg_catalog | ~~ | character  | text   | boolean  | matches LIKE expression 
pg_catalog | ~~ | name   | text   | boolean  | matches LIKE expression 
pg_catalog | ~~ | text   | text   | boolean  | matches LIKE expression 
(12 rows) 

第3行和第4行是我正在查找的操作员，但是desc ription对我来说有点不足。

Answer 1

~>=~，~<=~，~>~和~<~是text图案（或varchar，基本上是相同的）的运营商，它们各自的兄弟姐妹>=，<=，>和<的对应物。他们严格按字节值对字符数据进行排序，忽略任何排序规则设置（与其兄弟相对）。这使得它们更快，但对大多数语言/国家也无效。

“C”语言环境实际上与没有语言环境相同，表示没有整理规则。这就解释了为什么ORDER BY name USING ~<~和ORDER BY name COLLATE "C"最终会这样做。

在这个相关答案对dba.SE的最后一章详细解释：

• Pattern matching with LIKE, SIMILAR TO or regular expressions in PostgreSQL

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注意~~是用来实现SQL LIKE expression Postgres的运营商和与几乎没有关系以上。同样，~~*执行ILIKE。更多：

• ~~ Operator In Postgres
• Symfony2 Doctrine - ILIKE clause for PostgreSQL?
• PostgreSQL - text Array contains value similar to