符〜<〜Postgres裏

Question

^{（本this question一部分，但它是有點文不對題，所以我決定把它自身的問題。）}

我找不到什麼操作~<~是。 Postgres手冊只提及~和類似的運算符here，但沒有符號~<~。

當PSQL控制檯擺弄，我發現，這些命令給了相同的結果：

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

而且這些給出了相反的順序：

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

而且在波浪運營商的一些信息：

\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員，但是desc ription對我來說有點不足。

Answer 1

~>=~，~<=~，~>~和~<~是text圖案（或varchar，基本上是相同的）的運營商，它們各自的兄弟姐妹>=，<=，>和<的對應物。他們嚴格按字節值對字符數據進行排序，忽略任何排序規則設置（與其兄弟相對）。這使得它們更快，但對大多數語言/國家也無效。

「C」語言環境實際上與沒有語言環境相同，表示沒有整理規則。這就解釋了爲什麼ORDER BY name USING ~<~和ORDER BY name COLLATE "C"最終會這樣做。

在這個相關答案對dba.SE的最後一章詳細解釋：

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

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注意~~是用來實現SQL LIKE expression Postgres的運營商和與幾乎沒有關係以上。同樣，~~*執行ILIKE。更多：

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