在postgresql中将行转换为字符串

Posted 2023-02-16

【中文标题】在postgresql中将行转换为字符串

【英文标题】：convert rows to string in postgresql

【发布时间】：2014-02-26 20:41:44

【问题描述】：

表名是t1。字段名称为name1。 name1 有这样的值

-------------------------------------------+
+       name1                              +
--------------------------------------------
|    "a_2013,AcMaster,Master"              |
|   "b_2014,AcMaster,Master"               |
|   "c_2013,a_AcMaster,a_Master"           |
|    "d_2014,a_AcMaster,a_Master"          |
|__________________________________________|

但我想得到这样的结果

  master          acmaster               text
   Master          AcMaster                a_2013,b_2014
   a_Master        a_Master                c_2013,d_2014

所以我尝试这样

    select (string_to_array(schemaname,',')) [3] as master,(string_to_array(schemaname,','))
 [2] as acmaster,(string_to_array(schemaname,',')) [1] from appsetup.company2 
c2,appsetup.company1 c1,appsetup.companygroup cg where    c1.compno=c2.compno and 
cg.compgroupno=c1.compgroupno and c1.compno in (3,2) group by 
string_to_array(schemaname,',')) [3],
(string_to_array(schemaname,',')) [2],cg.compgroupno,schemaname order by 
cg.compgroupno

但它的回报

master          acmaster               text
   Master          AcMaster              ["a_2013","b_2014"]
   a_Master        a_Master              ["c_2013","d_2014"]

如何得到我想要的结果？

我正在使用 Postgresql 9.3

【参考方案1】：

你可以试试这个：

select string_agg(name1, ',') as Name1s
from t1

string_agg

【讨论】：

如果您要聚合的列类型不是文本，则需要添加类型转换：select string_agg(name1::text, ',') as Name1s from t1