Insert into a table values from another table using Oracle

Question

I have 2 tables ,

table 1 has the following fields ,

u_id    id      no
12      51      1
21      51      2
31      51      3
41      51      4
51      51      5
61      51      6
72      51      7
81      51      8
91      51      9
92      51      10

table 2 has the following fields,

id      one     two     three   four    five    six     seven   eight   nine    ten

51      12      21      31      41      51      61      72      81      91      92

I need to check the no. and the id from table 1 and insert the corresponding u_id into the table 2.

for eg. if the id = 51 and the no is 1, then I have to insert the u-id value into the column one in table 2,

and id = 51 and no = 2 then insert into column two and so on .. Please help . I am using Oracle.

Answer 1

If you want to create a new table or just need to return this set from database, you will require pivot table to do this...

select * from table 1

pivot (max (u_id) for id in ([1],[2],[3],[4],[5],[6],[7],[8],[9])[10]) as table 2

Answer 2

I don't think it can be done with a single query. You have to write a PLSQL block for it.

1. First list out all unique ids from table 1
2. Iterate it through a for-each and insert corresponding u_id in successive columns in table 2

Just a theoretical explanation.

Answer 3

id must be unique

select id,
sum(u_id*(if no = 1 then 1 else 0 endif)) as one,
sum(u_id*(if no = 2 then 1 else 0 endif)) as two,
sum(u_id*(if no = 3 then 1 else 0 endif)) as three,
sum(u_id*(if no = 4 then 1 else 0 endif)) as four,
sum(u_id*(if no = 5 then 1 else 0 endif)) as five,
sum(u_id*(if no = 6 then 1 else 0 endif)) as six,
sum(u_id*(if no = 7 then 1 else 0 endif)) as seven,
sum(u_id*(if no = 8 then 1 else 0 endif)) as eight,
sum(u_id*(if no = 9 then 1 else 0 endif)) as nine,
sum(u_id*(if no = 10 then 1 else 0 endif)) as ten
from table_1 group by id;

Answer 4

Is this what you are looking for:

// prepopulate missing table2 entries with 0s
insert into table2 (id, one, two, three, four, five, six, seven, eight, nine, ten)
    select distinct t1.id, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
    from   table1 t1
    where  t1.id not in (select id from table2 t2 where t1.id = t2.id);

// update table2 entries with the values from table1
update table2 
set one = (select u_id
          from   table1 t1
          where  t1.id = table2.id
          and    t1.no = 1);

update table2 
set two = (select u_id
          from   table1 t1
          where  t1.id = table2.id
          and    t1.no = 2);

// and so on....