create or replace function getstringlen(str in varchar2) return integer is result integer; i number; begin result := 0; if length(str) = 0 then return(result); end if; for i in 1 .. length(str) loop if ascii(substr(str, i, 1)) < 256 then result := result + 1; else result...
(1 行记录) postgres=# select octet_length('类'); octet_length --- 3 --->>>返回Byte的个数 (1 行记录) postgres=# select char_length('类'); char_length --- 1 --->>>返回字符(characters)的个数 (1 行记录) postgres=# select bit_length('类'); bit_length --- 24 --->>>返回...
The SUBSTRING() function extracts a portion of a string based on specified criteria, such as starting position and length. It can be tailored to extract characters from any point in the string and for any number of characters. 3.What are the main uses of the PostgreSQL SUBSTRING() function?
Introduction to PostgreSQL SUBSTRING() function The SUBSTRING() function allows you to extract a substring from a string and return the substring. Here’s the basic syntax of the SUBSTRING() function: SUBSTRING(string, start_position, length) In this syntax: string: This is an input string wit...
max_function_args (integer):最大函数参数,100 max_identifier_length (integer):最大标识符长度,63 字节 max_index_keys (integer):最大索引键,32 segment_size (integer) server_encoding (string):initdb, UTF-8 server_version (string) server_version_num (integer):150002,160000,比如 120007 代表 12.7...
string NOT LIKE pattern [ ESCAPE escape-character ] 每个pattern定义一个字串的集合。如果该string包含在pattern代表的字串集合里,那么LIKE表达式返回真。和我们想象的一样,如果 LIKE返回真,那么NOT LIKE表达式返回假,反之亦然。在pattern里的下划线(_)代表匹配任何单个字符,而一个百分号(%)匹配任何零或更多字符,...
还可以参阅Section 9.20中的string_agg。 Table 9-10. 内建转换 4.1 format 函数format根据一个格式字符串产生格式化的输出,其形式类似于 C 函数sprintf。 format(formatstr text [, formatarg"any"[, ...] ]) formatstr是一个格式字符串,它指定了结果应该如何被格式化。格式字符串中的文本被直接复制到结果中...
"string_data_length_mismatch", ERRCODE_STRING_DATA_LENGTH_MISMATCH }, { "string_data_right_truncation", ERRCODE_STRING_DATA_RIGHT_TRUNCATION }, { "substring_error", ERRCODE_SUBSTRING_ERROR }, { "trim_error", ERRCODE_TRIM_ERROR }, { "unterminated_c_string", ERRCODE_UNTERMINATED_C_STRING }...
PostgreSQL BIT_LENGTH() function with Example : The PostgreSQL bit_length function is used to count the number of bits in a specified string.
量测2D对象长度 ST_length2d(geometry) 量测3D对象长度 ST_length3d(geometry) 根据经纬度对象计算在地球曲面上的长度 ST_length_spheroid(geometry,spheroid) ST_length3d_spheroid(geometry,spheroid) 量测两个对象间距离 ST_distance(geometry, geometry) 量测两条线之间的最大距离 ST_max_distance(linestring,li...