PostgreSQL SUBSTRING() functionLast update on January 29 2025 10:50:23 (UTC/GMT +8 hours) SUBSTRING() functionThe PostgreSQL SUBSTRING() function is a powerful tool for text manipulation, allowing users to extract a sequence of characters from a given string. This function is essential for ...
substring(string from pattern for escape) text 抽取匹配SQL正则表达式的子字串 substring('Thomas' from '%#"o_a#"_' for '#') oma trim([leading | trailing | both] [characters] from string) text 从字串string的开头/结尾/两边/ 删除只包含characters(缺省是一个空白)的最长的字串 trim(both 'x...
1 fts=#createindexmail_messages_btreeonmail_messages(substring(body_plainfor2048)); 我们还将建立GiST索引: 1 fts=#createindexmail_messages_gistonmail_messages using gist(tsv); 在«vacuum full»后索引的大小: 1 2 3 4 5 6 7 fts=#selectpg_size_pretty(pg_relation_size('mail_messages_tsv_...
The REVERSE() function reverses the characters in the email address. The SUBSTR() function extracts a substring from the reversed email address, starting from the 4th character. The REVERSE() function is used again to reverse the extracted email ID back to its original order. ...
模式匹配:postgreSQL 提供三种类型正则表达式 , sql LIKE 操作符, posix 系列的 表达式, substring. stringLIKEpattern[ESCAPEescape-character]stringNOT LIKEpattern[ESCAPEescape-character] Everypatterndefines a set of strings. TheLIKEexpression returns true if thestringis contained in the set of strings repres...
[for int]) substring(string from pattern) trim([leading | trailing | both] [characters] fromstring) upper(string) 返回值 描述 示例 text 字符串连接 'Post' || 'greSQL' text 字符串和非字符串之间 的连接 'Value: ' || 42 int 字符串的 bit 数 bit_length('jose') int 字符串的字符数 ...
模式匹配:postgreSQL 提供三种类型正则表达式 , sql LIKE 操作符, posix 系列的 表达式, substring. stringLIKEpattern[ESCAPEescape-character]stringNOT LIKEpattern[ESCAPEescape-character] Everypatterndefines a set of strings. The LIKE expression returns true if thestringis contained in the set...
According to the standard, the first two characters of an error code denote a class of errors, while the last three characters indicate a specific condition within that class. Thus, an application that does not recognize the specific error code might still be able to infer what to do from ...
SUBSTRING(str FROM pos FOR len) The forms without a len argument return a substring from string str starting at position pos. The forms with a len argument return a substring len characters long from string str, starting at position pos. The forms that use FROM are standard SQL syntax. It...
Example #1: How Does SUBSTRING() Function Work in Postgres? Suppose we have to get the six characters from a string “commandprompt”. The sub-string should be extracted from the 8th index: SELECT SUBSTRING('commandprompt' from 8 for 6); ...