Question

I know how to create a sequence in pl sql. However, how would I set the values to all have say 3 digits? is there another sql statement to do this when I create a sequence?

so an example would be:

000
001
012
003

Thanks guys!

Answer 1

First, just to be clear, you do not create sequences in PL/SQL. You can only create sequences in SQL.

Second, if you want a column to store exactly three digits, you would need the data type to be VARCHAR2 (or some other string type) rather than the more common NUMBER since a NUMBER by definition does not store leading zeroes. You can, of course, do that, but it would be unusual.

That said, you can use the “fm009” format mask to generate a string with exactly 3 characters from a numeric sequence (the “fm” bit is required to ensure that you don’t get additional spaces– you could TRIM the result of the TO_CHAR call as well and dispense with the “fm” bit of the mask).

SQL> create table t( col1 varchar2(3) );

Table created.

SQL> create sequence t_seq;

Sequence created.

SQL> ed
Wrote file afiedt.buf

  1  insert into t
  2    select to_char( t_seq.nextval, 'fm009' )
  3      from dual
  4*  connect by level <= 10
SQL> /

10 rows created.

SQL> select * from t;

COL
---
004
005
006
007
008
009
010
011
012
013

10 rows selected.