How to split two columns into two rows using oracle sql? - sql

Question

for example I have a data below:
column1 column2 column3 column4 column5
A B 5 2 3
My desired table would be:
columnA
A
B
The condition to determine the splitting is if (column3 + column4)>5 otherwise no splitting.

Answer 1

union all:
select column1 as columnA from t where column3 + column4 > 5
union all
select column2 from t where column3 + column4 > 5 ;

Answer 2

I'm not sure I fully understood what you are looking for, but if you wan' to put a if, ele in the SELECT, you might wan't to use the CASE expression.
https://docs.oracle.com/cd/B19306_01/server.102/b14200/expressions004.htm

Answer 3

Use a LEFT JOIN (with join condition) or CROSS JOIN (no join condition) to a derived table that consists of 2 rows, then output the values via a case expression. Both approaches allow access to all columns for other conditions too.
SQL Fiddle
Oracle 11g R2 Schema Setup:
CREATE TABLE TABLE1
(COLUMN1 VARCHAR2(1), COLUMN2 VARCHAR2(1), COLUMN3 INT, COLUMN4 INT, COLUMN5 INT)
;
INSERT ALL
INTO TABLE1 (COLUMN1, COLUMN2, COLUMN3, COLUMN4, COLUMN5)
VALUES ('A', 'B', 5, 2, 3)
INTO TABLE1 (COLUMN1, COLUMN2, COLUMN3, COLUMN4, COLUMN5)
VALUES ('C', 'D', 1, 1, 1)
SELECT * FROM DUAL
Query 1:
select
case when lj.rn = 1 then t.column1 else t.column2 end as columnA
, t.column1
, t.column2
, t.column3
, t.column4
, t.column5
from table1 t
left join ( select 1 as rn from dual union all select 2 from dual ) lj
on (column3 + column4) > 5
Results:
| COLUMNA | COLUMN1 | COLUMN2 | COLUMN3 | COLUMN4 | COLUMN5 |
|---------|---------|---------|---------|---------|---------|
| A | A | B | 5 | 2 | 3 |
| B | A | B | 5 | 2 | 3 |
| D | C | D | 1 | 1 | 1 |
Query 2:
select
case when cj.rn = 1 then t.column1 else t.column2 end as columnA
, t.column1
, t.column2
, t.column3
, t.column4
, t.column5
from table1 t
cross join ( select 1 as rn from dual union all select 2 from dual ) cj
Results:
| COLUMNA | COLUMN1 | COLUMN2 | COLUMN3 | COLUMN4 | COLUMN5 |
|---------|---------|---------|---------|---------|---------|
| A | A | B | 5 | 2 | 3 |
| B | A | B | 5 | 2 | 3 |
| C | C | D | 1 | 1 | 1 |
| D | C | D | 1 | 1 | 1 |

Answer 4

Suppose I have table test with sample data
column1 | column2 | column3 | column4 | column5
-------------------------------------------------------
A | B | 5 | 2 | 3
C | D | 1 | 1 | 1
E | F | 4 | 5 | 1
Script for above sample data:-
CREATE TABLE TEST
(
column1 VARCHAR2(10),
column2 VARCHAR2(10),
column3 NUMBER(2),
column4 NUMBER(2),
column5 NUMBER(2)
);
INSERT INTO TEST VALUES('A','B',5,2,3);
INSERT INTO TEST VALUES('C','D',1,1,1);
INSERT INTO TEST VALUES('E','F',4,5,1);
COMMIT;
Below query will give required output:-
WITH tmp AS
(SELECT (CASE
WHEN column3 + column4 > 5 THEN
column1||','||column2
ELSE
NULL
END) columna,
column1,column2,column3,column4,column5
FROM TEST)
SELECT regexp_substr(columna,'[^,]+',1,LEVEL) columna,
column1,column2,column3,column4,column5
FROM tmp
CONNECT BY LEVEL <= regexp_count(columna, ',') + 1
AND PRIOR column1 = column1
AND PRIOR dbms_random.random IS NOT NULL;
Output:
columnA | column1 | column2 | column3 | column4 | column5
-------------------------------------------------------------------
A | A | B | 5 | 2 | 3
B | A | B | 5 | 2 | 3
| C | D | 1 | 1 | 1
E | E | F | 4 | 5 | 1
F | E | F | 4 | 5 | 1