说明:ASCII code of the first character of the argument. For UTF8 returns the Unicode code point of the character. For other multibyte encodings. the argument must be a strictly ASCII character. 得到某一个字符的Assii值 例子:ascii('x') = 120 函数:btrim(string text [, characters text]) ...
REPLACE(string, existion_string, [replacement_string]) 变量定义如下: string为字符表达式c existion_string为已存在的字符串。 replacement_string为用来替代的可选字符串。 例:使用REPLACE函数 显示了在Course表中如何使用REPLACE来改变课程名称(title):首先使用查询显示当前课程名称,UPDATE语句中使用REPLACE函数将SEMIN...
说明:ASCII code of the first character of the argument. For UTF8 returns the Unicode code point of the character. For other multibyte encodings. the argument must be a strictly ASCII character. 得到某一个字符的Assii值 例子:ascii('x') = 120 函数:btrim(string text [, characters text]) ...
FORMATFormat a string based on a templateFORMAT(‘Hello %s’,’PostgreSQL’)‘Hello PostgreSQL’ INITCAPConvert words in a string to title caseINITCAP(‘hI tHERE’)Hi There LEFTReturn the first n character in a stringLEFT(‘ABC’,1)‘A’ ...
ascii(<string>) PostgreSQL Version: 9.3 Pictorial Presentation of PostgreSQL ASCII() function Example: PostgreSQL ASCII() function : In the following example, PostgreSQL ascii function returns the code of the first character of the given string. ...
说明:Any character in string that matches a character in the from set is replaced by the corresponding character in the to set 将字符串中某些匹配的字符替换成指定字符串,目标字符与源字符都可以同时指定多个 例子:translate('12345', '14', 'ax') = a23x5 ...
PostgreSQL TRANSLATE() with Example : The PostgreSQL translate function is used to translate any character in the string by a character in replace_string. The characters in replace_string is corresponding to the characters in matching_string.
CREATE FUNCTION instr(varchar, integer) RETURNS integer AS $$ DECLARE v_string ALIAS FOR $1; index ALIAS FOR $2; BEGIN -- some computations using v_string and index here END; $$ LANGUAGE plpgsql; CREATE FUNCTION concat_selected_fields(in_t sometablename) RETURNS text AS $$ BEGIN RETURN...
(ColumnDef); n->colname = $1; n->typeName = $2; n->inhcount = 0; n->is_local = true; n->is_not_null = false; n->is_from_type = false; n->is_from_parent = false; n->storage = 0; n->raw_default = NULL; n->cooked_default = NULL; n->collClause = (Collate...
string NOT SIMILAR TO pattern [ESCAPE escape-character] SIMILAR TO操作符根据自己的模式是否匹配给定串而返回真或者假。 它和LIKE非常类似,只不过它使用 SQL 标准定义的正则表达式理解模式。 SQL 正则表达式是在LIKE标记和普通的正则表达式标记的奇怪的杂交。