[CLOSED] How to get the previous day of a day

Question

Hi all,
How do I minus a day from another day?
For example
Table1
Code Meaning
1 'Monday'
2 'Tuesday'
The result for the below query should be 'Monday'
select PreviousDayOf(Table1.Meaning)
from SomeTable, Table1
where SomeTable.Code = Table1.Code
and Table1.code = 2
Thank you for your time.
Message was edited by:
user594688

Answer 1

You could do a double DECODE. It may not be the best approach in the world but it may suit your needs.
Here is a sample:
SQL> CREATE TABLE table1(code number, meaning varchar2(15));
Table created.
SQL> INSERT INTO table1(code,meaning) VALUES (1,'Monday');
1 row created.
SQL> INSERT INTO table1(code,meaning) VALUES (2,'Tuesday');
1 row created.
SQL> SELECT * FROM table1;
      CODE MEANING                                                             
         1 Monday                                                              
         2 Tuesday                                                             
SQL> SELECT DECODE(DECODE(meaning,'Monday',1,'Tuesday',2)-1,1,'Monday',2,'Tuesday') FROM table1 WHERE code=2;
DECODE(                                                                        
Monday                                                                         
SQL> spool off;Hope this helps!