从函数查询

Question

我有这个查询

Select distinct a.name,
p1.ref as book,
p2.ref as text,
p3.ref as note
from library a
left join room p1 on a.id=p1.id 
left join room p2 on a.id=p2.id 
left join room p3 on a.id=p3.id 

我开始创建如下功能。函数的输出需要是上面的查询。 p1，p2和p3是动态生成的

rlsql varchar2(12000) := 'select distinct ';
rlsql := rlsql||'ref as '||c_var.name||',';
rlsql := rlsql||chr(13)||chr(10);
rlsql := rlsql||' from library';

rlsql := rlsql||' left join room on a.id='||c_var.id||' 

当我执行上述部分功能时，它返回我作为下面的示例

Select distinct 
ref as book from library,
ref as text from library,
ref as note from library

如何删除每行上的“from library”以及如何获取p1。 ，P2。 ，P3。动态

对此有任何帮助表示高度赞赏

Answer 1

删除这一行连接' from library'

的行

rlsql := rlsql||' from library';