Question

I have a table part with a few demo data as below in Oracle DB:

ID    NUMBER     DESCRIPTION
1     T00001     test
2     T00002     test
3     T00003     test
4     T00004     test
5     T00008     test
6     SG0001     test
7     SG0002     test
8     SG0003     test
9     SG0004     test
10    SG0006     test

The column NUMBER defines different category part with different predefined prefix and auto-incremental number suffix. Now in DB there have been some numbers missed so the continuity is broken. I want a SQL query or PL-SQL function with perfect performance to list the missed numbers:

e.g: for the above demo data. the following data should be returned:

 Category1 start with T: T00005,T00006,T00007 
 Category1 start with SG: SG0005

Anybody have ideas?

Answer 1

For SG:

WITH t AS ( 
    SELECT 
        0 as start_n, 
        p.a as end_n 
    FROM (
        SELECT MAX(TO_NUMBER(SUBSTR("NUMBER", 3))) a FROM Part p2 
        WHERE "NUMBER" LIKE 'SG%') p
)
SELECT 
    'SG' || LPAD(r.cur_num, 4, '0') AS missing_expr
FROM 
    (SELECT t.start_n + level - 1 AS cur_num FROM t CONNECT BY t.start_n + level - 1 <= t.end_n) r
WHERE 
    NOT EXISTS(
        SELECT * FROM part p WHERE p."NUMBER" = 'SG' || LPAD(r.cur_num, 4, '0')
    )
ORDER BY missing_expr ASC;

For T:

WITH t AS ( 
    SELECT 
        0 as start_n, 
        p.a as end_n 
    FROM (
        SELECT MAX(TO_NUMBER(SUBSTR("NUMBER", 2))) a FROM Part p2 
        WHERE "NUMBER" LIKE 'T%') p
)
SELECT
    'T' || LPAD(r.cur_num, 5, '0') AS missing_expr
FROM 
    (SELECT t.start_n + level - 1 AS cur_num FROM t CONNECT BY t.start_n + level - 1 <= t.end_n) r
WHERE 
    NOT EXISTS(
        SELECT * FROM part p WHERE p.number = 'T' || LPAD(r.cur_num, 5, '0')
    )
ORDER BY missing_expr ASC