PostgreSQL 常用对象 PostgreSQL 字符串函数主要用于字符串操作。下表详细介绍了重要的字符串函数 序号函数描述 1 ASCII() 返回最左边字符的数值 2 BIT_LENGTH() 以位为单位返回参数的长度 3 CHAR_LENGTH() 返回参数中的字符数 4 CHARACTER_LENGTH() CHAR_LENGTH() 的同义词 5 CONCAT_WS() 返回连接分隔符 6 ...
FROMmysql.help_topic WHEREhelp_topic_id < LENGTH(@result)-LENGTH(REPLACE(@result,',',''))+1; SELECTSUBSTRING_INDEX('A,,B,C,D',',',1); SELECTSUBSTRING_INDEX('A,,B,C,D',',',2); SELECTSUBSTRING_INDEX('A,,B,C,D',',',-2); SELECTSUBSTRING_INDEX('A,,B,C,D',',',-1);...
1 row in set (0.00 sec) 1. 2. 3. 4. 5. 6. 7. CHAR_LENGTH(str) 返回字符串str的长度,以字符为单位。多字节字符算作单个字符。这意味着对于包含五个两个字节的字符串,LENGTH()返回10,而CHAR_LENGTH()返回5。 AI检测代码解析 testdb=# SELECT CHAR_LENGTH('text'); +---+ | CHAR_LENGTH('...
insert into test_收费项目表(ID,收费科室,收费项目) values (i,'内科'||(i),'内科收费项目'||(i)); end loop; for i in 1..m loop insert into test_收费项目表(ID,收费科室,收费项目) values ((i+10),'外科'||(i),'外科收费项目'||(i)); end loop; for i in 1..m loop insert int...
Find a number of bytes in a string.OCTET_LENGTH ('AB') = 2 OCTET_LENGTH ('Ö') = 2 OCTET_LENGTH ('?') = 4Postgres String Functions: ModificationString concatenation.'Postgre' || 'SQL' = 'PostgreSQL' 'Value: ' || 42 = 'Value: 42'Remove the longest string containing only the ...
Returns the decimal representation in the database character set of the first character of char: ascii('a')→ 97. LENGTH Return the length of char: length ('John S.')→ 7. To create the PATINDEX function, use the following code snippet. Note the 0...
Author: TheTable Length: 3 MINS Type: GUIDE Published: 2023-09-14 intro When navigating the realm of PostgreSQL, developers often stumble upon a myriad of functions, with the STRING_AGG() function being a frequently utilized, yet occasionally misunderstood, tool. This guide seeks to demystify ...
LENGTH(productCode)-INSTR(productCode,'_')) productNoFROMproducts; 拼接字符串 MySQL字符串连接符是空格:select 'hello' 'world';(PostgreSQL和Oracle的是||, SQL Server的是+); MySQL还提供了两个拼接字符串的方法: concat concat_ws带分割符号
PostgreSQL provides a built-in function namedSUBSTRING()that extracts a substring from any specific string. TheSUBSTRING()function accepts three parameters: a string, starting position, and length. The starting position” and “length” parameters are optional that can be skipped depending on ...
int length(string A):返回字符串的长度。 int locate(string substr, string str[, int pos]):返回 pos 位置之后 substr 在 str 中第一次出现的位置。 string lower(string A) lcase(string A): 返回全部字符转为小写之后的字符串。例如,lower(‘fOoBaR’) 结果为 ‘foobar’。