Merge not functioning

Question

Hi,
I have a table parameters where I store different parameters. Now, I created a merge statement, so that if the parameter exists, it is updated, else it should be created. The update works... the insert does not!
My parameters table consists of 2 columns: parameter (=parametername) and value (=value of the parameter).
merge into parameters p
using (select parameter, value
       from   parameters
       where  parameter = 'TEST') p2
on    (p.parameter = p2.parameter)
when matched then
update set value = 33
when not matched then
insert (parameter, value) values ('TEST',34)
;What's going wrong??...
Message was edited by:
Voxie2

Answer 1

It seems you want to make sure the record ('TEST',34) is in your parameter table. If it not there already, you want to insert the record, and if it is there, you want to make sure it has the value 34.
In that case the record ('TEST',34) should not be selected from the parameter table, because it might not be there and then your merge won't work. Select the record from dual and it will work:
SQL> create table parameters (parameter,value)
  2  as
  3  select 'parameter1', 1 from dual
  4  /
Tabel is aangemaakt.
SQL> merge into parameters p
  2  using (select 'TEST' parameter, 34 value from dual) input
  3     on (p.parameter = input.parameter)
  4   when matched then
  5        update set value = input.value
  6   when not matched then
  7        insert values (input.parameter,input.value)
  8  /
1 rij is samengevoegd.
SQL> select * from parameters
  2  /
PARAMETER       VALUE
parameter1          1
TEST               34
2 rijen zijn geselecteerd.
SQL> update parameters
  2     set value = 20
  3   where parameter = 'TEST'
  4  /
1 rij is bijgewerkt.
SQL> select * from parameters
  2  /
PARAMETER       VALUE
parameter1          1
TEST               20
2 rijen zijn geselecteerd.
SQL> merge into parameters p
  2  using (select 'TEST' parameter, 34 value from dual) input
  3     on (p.parameter = input.parameter)
  4   when matched then
  5        update set value = input.value
  6   when not matched then
  7        insert values (input.parameter,input.value)
  8  /
1 rij is samengevoegd.
SQL> select * from parameters
  2  /
PARAMETER       VALUE
parameter1          1
TEST               34
2 rijen zijn geselecteerd.Regards,
Rob.