GreenPlum常用字符串函数

GreenPlum常用字符串函数如下：

测试代码：

eda_gp=> select 'green'||'plum' as dbname;
  dbname   
-----------
 greenplum
(1 row)

eda_gp=> select length('greenplum');
 length 
--------
      9
(1 row)

eda_gp=> select position('plum' in 'greenplum');
 position 
----------
        6
(1 row)

eda_gp=> select substring('greenplum' from 6 for 3);
 substring 
-----------
 plu
(1 row)

eda_gp=> select trim(both 'x' from 'xgreenplumxx');
   btrim   
-----------
 greenplum
(1 row)

eda_gp=> select upper('greenplum');
   upper   
-----------
 GREENPLUM
(1 row)

eda_gp=> select lower('GREENPLUM');
   lower   
-----------
 greenplum
(1 row)

eda_gp=> select overlay('greenxxxm' placing 'plu' from 6 for 3);
  overlay  
-----------
 greenplum
(1 row)

eda_gp=> select replace('greenplum','plum','xxx');
 replace  
----------
 greenxxx
(1 row)

eda_gp=> select split_part('abc|def|ght','|',3);
 split_part 
------------
 ght
(1 row)