Query works in SQL Server, trying to replicate in Oracle - sql

Question

I have a query that works as intended in SQL Server, but when I try to replicate it in Oracle, it doesn't work.
In SQL Server, it returns Column1 with 5 characters.
In Oracle, it is returning the original values.
Oracle syntax isn't my strong point, how can I get this to work, any suggestions would be appreciated
SELECT
CASE
WHEN Column1 LIKE '__-____'
THEN CONCAT('000', (SUBSTR(LTRIM(RTRIM(Column1)), 1, 2)))
WHEN Column1 LIKE '___-____'
THEN CONCAT('00', (SUBSTR(LTRIM(RTRIM(Column1)), 1, 3)))
WHEN Column1 LIKE '_______-_____'
THEN (SUBSTR(LTRIM(RTRIM(Column1)), 3, 5))
ELSE Column1
END AS NewColumn
FROM
schema.table1
Here it is again with a CTE so you can see it works as intended in SQL Server:
WITH cte_test AS
(
SELECT '12-3456' AS Column1
UNION ALL
SELECT '78-9101'
UNION ALL
SELECT '1234567-89101'
UNION ALL
SELECT '123-4321'
)
SELECT
CASE
WHEN Column1 LIKE '__-____'
THEN CONCAT('000', (SUBSTRING(LTRIM(RTRIM(Column1)), 1, 2)))
WHEN Column1 LIKE '___-____'
THEN CONCAT('00', (SUBSTRING(LTRIM(RTRIM(Column1)), 1, 3)))
WHEN Column1 LIKE '_______-_____'
THEN (SUBSTRING(LTRIM(RTRIM(Column1)), 3, 5))
ELSE Column1
END AS NewColumn
FROM
cte_test

Answer 1

The issue is that you've declared the column in the Oracle table as char(20). char(20) is a fixed width data type so it will always be space padded out to 20 characters. Given your sample data, that wastes space and means that neither of your like clauses are going to match the sample data because of the trailing spaces. You really want to declare the column in the table as varchar2(20) so that it is not blank padded.
If you just take the CTE from your SQL Server example and use it with your Oracle code, the query returns what you want because Oracle treats the column in the CTE as a varchar2
WITH cte_test AS
(
SELECT '12-3456' AS Column1 from dual
UNION ALL
SELECT '78-9101' from dual
UNION ALL
SELECT '1234567-89101' from dual
UNION ALL
SELECT '123-4321' from dual
)
SELECT
CASE
WHEN Column1 LIKE '__-____'
THEN CONCAT('000', (SUBSTR(LTRIM(RTRIM(Column1)), 1, 2)))
WHEN Column1 LIKE '___-____'
THEN CONCAT('00', (SUBSTR(LTRIM(RTRIM(Column1)), 1, 3)))
WHEN Column1 LIKE '_______-_____'
THEN (SUBSTR(LTRIM(RTRIM(Column1)), 3, 5))
ELSE Column1
END AS NewColumn
FROM cte_test
If you create the table as a char(20) and insert the data, it gets space padded so the like statements don't do what you want
create table char_test( column1 char(20) );
insert into char_test
WITH cte_test AS
(
SELECT '12-3456' AS Column1 from dual
UNION ALL
SELECT '78-9101' from dual
UNION ALL
SELECT '1234567-89101' from dual
UNION ALL
SELECT '123-4321' from dual
)
select * from cte_test;
SELECT
CASE
WHEN Column1 LIKE '__-____'
THEN CONCAT('000', (SUBSTR(LTRIM(RTRIM(Column1)), 1, 2)))
WHEN Column1 LIKE '___-____'
THEN CONCAT('00', (SUBSTR(LTRIM(RTRIM(Column1)), 1, 3)))
WHEN Column1 LIKE '_______-_____'
THEN (SUBSTR(LTRIM(RTRIM(Column1)), 3, 5))
ELSE Column1
END AS NewColumn
FROM char_test
You can work around that by trimming Column1 before doing the like
SELECT
CASE
WHEN trim(Column1) LIKE '__-____'
THEN CONCAT('000', (SUBSTR(Column1, 1, 2)))
WHEN trim(Column1) LIKE '___-____'
THEN CONCAT('00', (SUBSTR(Column1, 1, 3)))
WHEN trim(Column1) LIKE '_______-_____'
THEN (SUBSTR(Column1, 3, 5))
ELSE Column1
END AS NewColumn
FROM char_test
But a better solution would be to declare the column as varchar2 in the first place so that you don't have the space padding to work around
create table varchar_test( column1 varchar2(20) );
insert into varchar_test
WITH cte_test AS
(
SELECT '12-3456' AS Column1 from dual
UNION ALL
SELECT '78-9101' from dual
UNION ALL
SELECT '1234567-89101' from dual
UNION ALL
SELECT '123-4321' from dual
)
select * from cte_test;
SELECT
CASE
WHEN Column1 LIKE '__-____'
THEN CONCAT('000', SUBSTR(Column1, 1, 2))
WHEN Column1 LIKE '___-____'
THEN CONCAT('00', SUBSTR(Column1, 1, 3))
WHEN Column1 LIKE '_______-_____'
THEN (SUBSTR(Column1, 3, 5))
ELSE Column1
END AS NewColumn
FROM varchar_test
Here is a fiddle that shows the various options.

Answer 2

Oracle alternative which (in temp CTE) extracts the first part of the string (up to the minus sign), and then - depending on its length - left pads it with zeros up to 5 characters in length, or takes the last 5 characters):
SQL> WITH cte_test AS
2 (
3 SELECT '12-3456' AS Column1 from dual
4 UNION ALL
5 SELECT '78-9101' from dual
6 UNION ALL
7 SELECT '1234567-89101' from dual
8 UNION ALL
9 SELECT '123-4321' from dual
10 ),
11 temp as
12 (select column1,
13 substr(column1, 1, instr(column1, '-') - 1) val
14 from cte_Test
15 )
16 select column1,
17 lpad(case when length(val) < 5 then val
18 else substr(val, -5)
19 end, 5, '0'
20 ) as result
21 from temp;
COLUMN1 RESULT
------------- --------------------
12-3456 00012
78-9101 00078
1234567-89101 34567
123-4321 00123
SQL>

Answer 3

You want something like:
SELECT CASE
WHEN Column1 LIKE '__-____ '
THEN '000' || SUBSTR(Column1, 1, 2)
WHEN Column1 LIKE '___-____ '
THEN '00' || SUBSTR(Column1, 1, 3)
WHEN Column1 LIKE '_______-_____ '
THEN SUBSTR(Column1, 3, 5)
ELSE Column1
END AS NewColumn
FROM schema.table1
or:
SELECT CASE
WHEN REGEXP_LIKE( Column1, '^\d{2}-\d{4}\s*$' )
THEN '000' || SUBSTR(Column1, 1, 2)
WHEN REGEXP_LIKE( Column1, '^\d{3}-\d{4}\s*$' )
THEN '00' || SUBSTR(Column1, 1, 3)
WHEN REGEXP_LIKE(Column1, '^\d{7}-\d{5}\s*$' )
THEN SUBSTR(Column1, 3, 5)
ELSE Column1
END AS NewColumn
FROM schema.table1
Or, more simply:
SELECT SUBSTR(
'000' || SUBSTR(column1, 1, INSTR(column1, '-') - 1),
-5
) AS newcolumn
FROM schema.table1
Which, for the sample data:
CREATE TABLE schema.table1( column1 CHAR(20) );
INSERT INTO schema.table1(column1)
SELECT '12-3456' FROM DUAL UNION ALL
SELECT '78-9101' FROM DUAL UNION ALL
SELECT '1234567-89101' FROM DUAL UNION ALL
SELECT '123-4321' FROM DUAL;
All output:
NEWCOLUMN
00012
00078
34567
00123
db<>fiddle here