1.求字持串的长度LENGTH 您可用LENGTH函数求字符串的长度。LENGTH返回一个数值。该值等于参数中的字符个数。 例:使用LENGTH函数 SQL>select Last_Name, length(Last_Name) from customer order by LastName; 2.使用SUBSTR函数从字符串中提取子串 语法: SUBSTR函数的语法如下: SUBSTR(string, string charcter, numb...
PostgreSQL offers several built-in string functions to calculate the string’s length, for example, theBIT_LENGTH(), CHAR_LENGTH(),etc. Among them, the most popularly used function is theLENGTH()function which takes a string and retrieves its total length. For instance, passing "hello" to ...
bit_length(string) 函数计算字符串包含的比特数;length(string)/char_length(string)/character_length(string) 函数计算字符串包含的字符数;octet_length(string) 函数计算字符串包含的字节数。 SELECT bit_length('jose'), length('jose'), octet_length('jose'); | bit_length | length | octet_length |...
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...
create or replace function random_string(length integer) returns text as $$ declare chars text[] := '{0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z}'; ...
PostgreSQL OCTET_LENGTH() function with Example : The PostgreSQL octet_length function is used to count the number of bytes in a specified string.
"string_data_length_mismatch", ERRCODE_STRING_DATA_LENGTH_MISMATCH }, { "string_data_right_truncation", ERRCODE_STRING_DATA_RIGHT_TRUNCATION }, { "substring_error", ERRCODE_SUBSTRING_ERROR }, { "trim_error", ERRCODE_TRIM_ERROR }, { "unterminated_c_string", ERRCODE_UNTERMINATED_C_STRING }...
CREATE OR REPLACE FUNCTION generate_random_string(length INTEGER) RETURNS VARCHAR LANGUAGE plpgsql AS $$ DECLARE result VARCHAR(255) := ''; chars TEXT[] := ARRAY['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v'...
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,...
] ) CREATE TYPE name ( INPUT = input_function, OUTPUT = output_function [, RECEIVE = receive_function ] [, SEND = send_function ] [, ANALYZE = analyze_function ] [, INTERNALLENGTH = { internal_length | VARIABLE } ] [, PASSEDBYVALUE ] [, ALIGNMENT = alignment ] [, STORAGE = stor...