在PostgreSQL中,我们可以使用chr函数将ASCII码转换为字符,结合random函数生成随机数,从而构造出随机字符串。此外,我们还可以使用generate_series函数来重复生成随机字符的过程,以达到指定长度的随机字符串。 3. 编写SQL语句 以下是一个生成指定长度随机字符串的SQL语句示例: sql WITH RECURSIVE random_string AS ( SELECT...
--Function:--Generate a random string array--Parameters:--str_length: Length of string--max_length: Maximum length of the array--fixed_length: Whether the length of array is fixed. If it is true, the length of array will match max_length.createorreplacefunctiongen_random_string_array(str...
COMMENT ON FUNCTION generate_random_string IS $docstring$ Generate a random string at a given length from a list of possible characters. Parameters: - length (int): length of the output string - characters (text): possible characters to choose from Example: db=# SELECT generate_random_string(...
The PostgreSQL Provides a random() function to generate a random string with all the possible different numbers, character and symbol. We can also use random() function with cryptography or encryption function to generate a fixed length binary string. ...
create or replace function random_string(integer) returns text as $body$ select array_to_string(array(select substring('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz' FROM (ceil(random()*62))::int FOR 1) FROM generate_series(1, $1)), ''); ...
PostgreSQL：⼀种⽤于⽣成随机字符串的⽅法 create or replace function random_string(integer)returns text as $body$ select array_to_string(array(select substring('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz' FROM (ceil(random()*62))::int FOR 1) FROM generate_series(1, $1...
CREATE OR REPLACE FUNCTION generate_random_string(length INTEGER) RETURNS VARCHAR LANGUAGE plpgsql AS $$ DECLARE result VARCHAR(255) := ''; chars TEXT[] := ARRAY['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v'...
select string_agg(substring('0123456789abcdefghjklmnopqrstuvwxyz', round(random() * 40)::integer, 1), '') from generate_series(1, 10); 1. 2. string_agg()是 聚合函数,用于将一列字符串连接成一个字符串 substring()用于从一个字符串中提取子串,substring(string, start, length) ...
create or replace function gen_hanzi(int) returns text as $$ declare res text; begin if $1 >=1 then select string_agg(chr(19968+(random()*20901)::int), '') into res from generate_series(1,$1); return res; end if; return null; end; $$ language plpgsql strict; 使用函数,生成...
pglz_test=#INSERTINTOmessagesSELECT(SELECTstring_agg(chr(floor(random()*26)::int+65),'')FROMgenerate_series(1,10000))FROMgenerate_series(1,10000);INSERT010000Time:4889.017ms(00:04.889)pglz_test=# 同时我们在启用了 LZ4 后,来查看两个不同压缩方式后的表的大小,可以明显的看出,使用LZ4的表大小是...