Migration of Oracle SQL to DB2 SQL

The following articles mainly focus on the migration solution from Oracle SQL to DB2 SQL. Migration from Oracle SQL to DB2 SQL has become very popular, if you want to know more about its practical application, you can browse the following articles and I believe it will be helpful to you.

1. decode in cancel

DB2 solution: Use case conditional expressions.

Two syntax modes of case:

(1) CASE

WHEN condition THEN result 1

ELSE result 2

END

(2) CASE expression 1

WHEN expression 2 THEN result 1

ELSE result 2

END

The above WHEN can be repeated multiple times, just like the expression of SWITCH... CASE in C.

For example:

 
 

  
  
SELECT ORDNO,CUSNO,  
  
  
CASE MONTH(SHIPDATE)  
  
  
WHEN ´´01´´ THEN ´´Jan´´  
  
  
WHEN ´´02´´ THEN ´´Feb´´  
  
  
WHEN ´´03´´ THEN ´´Mar´´  
  
  
WHEN ´´04´´ THEN ´´Apr´´  
  
  
WHEN ´´05´´ THEN ´´May´´  
  
  
WHEN ´´06´´ THEN ´´Jun´´  
  
  
WHEN ´´07´´ THEN ´´Jul´´  
  
  
WHEN ´´08´´ THEN ´´Aug´´  
  
  
WHEN ´´09´´ THEN ´´Sep´´  
  
  
WHEN ´´10´´ THEN ´´Oct´´  
  
  
WHEN ´´11´´ THEN ´´Nov´´  
  
  
WHEN ´´12´´ THEN ´´Dec´´  
  
  
END  
  
  
FROM FILE  
 
 

Application instance:

Oracle SQL:

 
 

  
  
select decode(t.organtypecode, 
´´D´´, t.parent, ´´S´´, t.parent, t.id)  
  
  
from A_ORGAN t  
  
  
where t.parent = 35 
  
  
DB2 SQL：  
  
  
select case x.organtypecode  
  
  
when ´´D´´ then  
  
  
x.parent  
  
  
when ´´S´´ then  
  
  
x.parent  
  
  
else  
  
  
x.id  
  
  
end  
  
  
from a_Organ x  
  
  
where x.parent = 35;  
 
 

2. Start with... Connect By recursive query in Oracle

DB2 solution: Use the with public recursive expression.

DB2 solution: Use case conditional expressions.

Oracle SQL:

 
 

  
  
select t.id  
  
  
from a_organ t  
  
  
start with t.id in (select decode(t.organtypecode,  
  
  
´´D´´,  
  
  
t.parent,  
  
  
´´S´´,  
  
  
t.parent,  
  
  
t.id)  
  
  
from A_ORGAN  
  
  
where t.id = 35)  
  
  
connect by t.parent = prior t.id  
  
  
DB2 SQL：  
  
  
WITH FKK(id) as  
  
  
(select o.id from a_organ o  
  
  
where o.id=35 
  
  
UNION ALL  
  
  
select case x.organtypecode  
  
  
when ´´D´´ then x.parent  
  
  
when ´´S´´ then x.parent  
  
  
else x.id  
  
  
end  
  
  
from FKK fk, a_organ x  
  
  
where fk.id=x.parent)  
  
  
select distinct id from FKK;  
 
 

The above content is a description of the migration solution from Oracle SQL to DB2 SQL, hoping to help you in this regard.