通过multi regexp_substr连接一个col

Question

我尝试使用下面的代码，但是我无法获取每个别名的值，它只允许我对一个别名使用connect by

select regexp_substr(test_col,'[^,]+[^,]', 1,1 ) as first_occur,
       regexp_substr(test_col,'[^,]+[^,]', 1,2 ) as second_occur,
       regexp_substr(test_col,'[^,]+[^,]', 1,3 ) as third_occur,
       regexp_substr(test_col,'[^,]+[^,]', 1,4 ) as forth_occur,
       regexp_substr(test_col,'[^,]+[^,]', 1,5 ) as fifth_occur,
       regexp_substr(test_col,'[^,]+[^,]', 1,6 ) as sixth_occur,
       regexp_substr(test_col,'[^,]+[^,]', 1,7 ) as seventh_occur,
       regexp_substr(test_col,'[^,]+[^,]', 1,8 ) as eighth_occur,
       regexp_substr(test_col,'[^,]+[^,]', 1,9 ) as ninth_occur,
       regexp_substr(test_col,'[^,]+[^,]', 1,10 ) as thenth_occur
       from demo_live
       CONNECT by 
       regexp_substr(test_col,'[^,]+[^,]', 1,1 )is not null,
       regexp_substr(test_col,'[^,]+[^,]', 1,2 )is not null,
       regexp_substr(test_col,'[^,]+[^,]', 1,3 )is not null,
       regexp_substr(test_col,'[^,]+[^,]', 1,4 )is not null,
       regexp_substr(test_col,'[^,]+[^,]', 1,5 )is not null,
       regexp_substr(test_col,'[^,]+[^,]', 1,6 )is not null,
       regexp_substr(test_col,'[^,]+[^,]', 1,7 )is not null,
       regexp_substr(test_col,'[^,]+[^,]', 1,8 )is not null,
       regexp_substr(test_col,'[^,]+[^,]', 1,9 )is not null,
       regexp_substr(test_col,'[^,]+[^,]', 1,10 )is not null;

我只有一栏，日期看起来像：

val1,val2,,val3,val4,val5
TS1,TS2,,,,TS3,TS4,TS5

expected result:
col1  col2   col3  col4  col4                 
val1  val2   val3  val4  val5
TS1   TS2    TS3   TS4   TS5