getting latest filled row

[shoonya]

i am having a table

table : t1
a1 serial
a2 varchar(20)

now since a1 will be automatically generated so i am using

insert into t1(a2) values ('foo');

now i want to get the a1 value corresponding to this value

although

max(a1)

is working but when too many users will be logged in then it will create problems

any suggestion ??

shoonya

[r035198x]

i am having a table

table : t1
a1 serial
a2 varchar(20)

now since a1 will be automatically generated so i am using

insert into t1(a2) values ('foo');

now i want to get the a1 value corresponding to this value

although

max(a1)

is working but when too many users will be logged in then it will create problems

any suggestion ??

shoonya

I don't get something or you're missing the fact that you can do

select a1 from t1 where a2 = 'foo'

[shoonya]

but a2 is not unique man..
a1 is the primary key here

shoonya

[r035198x]

but a2 is not unique man..
a1 is the primary key here

shoonya

Yep, I was missing something then .

[shoonya]

okk
so any suggestions now ??

shoonya

[r035198x]

okk
so any suggestions now ??

shoonya

Sorry I'd forgotten about this. Well I don't think it's possible to avoid going through all the values. The options are:

• If you used a sequence to generate the IDs you can do

  SELECT currval('sequence_id_seq');

• SELECT id FROM tableName ORDER BY id DESC limit 1;

• Try also

  SELECT LAST_INSERT_ID();

  but I'm not sure if this works in PostgreSQL

[shoonya]

there is a possibility that another user might insert some data in between
so that the query results are not consistent

i hope you are getting the problem

shoonya

[r035198x]

there is a possibility that another user might insert some data in between
so that the query results are not consistent

i hope you are getting the problem

shoonya

If you use SELECT currval(sequence_id_seq'); there will be no problem because the specs say it handles multiple connections correctly.

[r035198x]

If you use SELECT currval(sequence_id_seq'); there will be no problem because the specs say it handles multiple connections correctly.

By the way I got that from here.

[shoonya]

thanks a lot man

shoonya