标簽
PostgreSQL , Oracle , 字元串分割
https://github.com/digoal/blog/blob/master/201804/20180410_02.md#%E8%83%8C%E6%99%AF 背景
Oracle中字元串分割,比較麻煩,可能需要寫PL/SQL來實作。
create or replace TYPE "STRINGS_TABLE" is table of varchar2(2000)
create or replace FUNCTION highsoft_split(
p_str IN long, --VARCHAR2,
p_delimiter IN VARCHAR2)
RETURN strings_table IS
j INT := 0;
i INT := 1;
len INT := 0;
len1 INT := 0;
str long;--VARCHAR2(2000);
str_split strings_table := strings_table();
BEGIN
len := LENGTH(p_str);
len1 := LENGTH(p_delimiter);
WHILE j < len LOOP
j := INSTR(p_str, p_delimiter, i);
IF j = 0 THEN
j := len;
str := SUBSTR(p_str, i);
str_split.EXTEND;
str_split(str_split.COUNT) := str;
IF i >= len THEN
EXIT;
END IF;
ELSE
str := SUBSTR(p_str, i, j - i);
i := j + len1;
str_split.EXTEND;
str_split(str_split.COUNT) := str;
END IF;
END LOOP;
RETURN str_split;
END highsoft_split;
效果如下
SQL> select * from table(highsoft_split('abc,d,e,f,g',','));
COLUMN_VALUE
--------------------------------------------------------------------------------
abc
d
e
f
g
https://github.com/digoal/blog/blob/master/201804/20180410_02.md#postgresql-%E5%AD%97%E7%AC%A6%E4%B8%B2%E5%88%86%E5%89%B2 PostgreSQL 字元串分割
PostgreSQL 的字元串處理功能非常強大,已經内置了蠻多可選的分隔函數
List of functions
Schema | Name | Result data type | Argument data types | Type
------------+-----------------------+------------------+------------------------+--------
pg_catalog | regexp_match | text[] | text, text | normal
pg_catalog | regexp_match | text[] | text, text, text | normal
pg_catalog | regexp_matches | SETOF text[] | text, text | normal
pg_catalog | regexp_matches | SETOF text[] | text, text, text | normal
pg_catalog | regexp_replace | text | text, text, text | normal
pg_catalog | regexp_replace | text | text, text, text, text | normal
pg_catalog | regexp_split_to_array | text[] | text, text | normal
pg_catalog | regexp_split_to_array | text[] | text, text, text | normal
pg_catalog | regexp_split_to_table | SETOF text | text, text | normal
pg_catalog | regexp_split_to_table | SETOF text | text, text, text | normal
pg_catalog | split_part | text | text, text, integer | normal
效果舉例
postgres=# select regexp_split_to_array('a,b,c,d,e',',');
regexp_split_to_array
-----------------------
{a,b,c,d,e}
(1 row)
postgres=# select regexp_split_to_table('a,b,c,d,e',',');
regexp_split_to_table
-----------------------
a
b
c
d
e
(5 rows)
當然,我們也可以通過plpgsql,plpython, plperl, pljava, pllua, 等函數語言來擴充PG的資料庫端計算能力。