I have two tables.
Table 1
ID STRING
1 ABC
2 CDE
3 FGH
Table 2
ID STRING
1 xyz
2 uvw
4 abc
I want the output as
ID STRING STRING2
1 ABC xyz
2 CDE uvw
3 FGH null
4 null abc
which join should I use. Is it possible to do this in simple SQL query?
with
t1 as
(select 1 id, 'ABC' string from dual
union
select 2, 'CDE' from dual
union
select 3, 'FGH' from dual
),
t2 as
(select 1 id, 'xyz' string from dual
union
select 2, 'uvw' from dual
union
select 4, 'abc' from dual)
select COALESCE(t1.id,t2.id) id, t1.string, t2.string string2
from t1 full outer join t2 on (t1.id = t2.id)
order by 1
What you can do is use Union to combine two different result sets. That will give you exactly what you're looking for:
SELECT tab1.ID,
tab1.name,
tab2.name2
FROM tab1 tab1
LEFT JOIN tab2 tab2 ON tab1.ID = tab2.ID
UNION
SELECT tab2.ID,
tab1.name,
tab2.name2
FROM tab1 tab1
RIGHT JOIN tab2 tab2 ON tab1.ID = tab2.ID
You can see that here-> http://sqlfiddle.com/#!4/cf9e2/10
Hope this helps!!!
I guess a full join would be correct
select * from tab1 t1 full join tab2 t2 on t1.id = t2.id
Related
Hi I am trying to filter data with dates between but it insert null 0 rows created its cross joining table I am not aware is there problem due to cross joining or something else. There is no error message
without dates it works fine any solution Please
insert into PAY_IN_OUT2 (EMP_CODE, DATE_IN, DATE_OUT, ATT_DATE, DATE_INA, DATE_OUTA, DATE_INB, DATE_OUTB, DATE_INC, DATE_OUTC, ATT_PRESENT)
select a.EMPLOYEE_ID1, b.DT, b.DT1, B.ATT_DT, B.DT3, B.DT4, B.DT4, B.DT5, B.DT5, B.DT3, 'P'
from CALENDAR_DATES4 b cross join EMPLOYEES a
WHERE A.EMPLOYEE_ID1 BETWEEN 70001 AND 70009
AND B.ATT_DT BETWEEN TO_DATE('10/02/2021', 'DD/MM/YYYY') AND TO_DATE('20/02/2021', 'DD/MM/YYYY') ;
without this its working fine but I have to filter this with dates AND B.ATT_DT BETWEEN TO_DATE('10/02/2021', 'DD/MM/YYYY') AND TO_DATE('20/02/2021', 'DD/MM/YYYY')
If you're cross joining two tables and filtering on each table, and you end up selecting 0 rows, then at least one of your predicates is causing no rows to be returned.
For example, here's a set of queries demonstrating some different results, depending on what the predicates cause to be returned:
WITH t1 AS (SELECT 1 ID, 10 val FROM dual UNION ALL
SELECT 2 ID, 20 val FROM dual UNION ALL
SELECT 3 ID, 30 val FROM dual UNION ALL
SELECT 4 ID, 40 val FROM dual UNION ALL
SELECT 5 ID, 50 val FROM dual),
t2 AS (SELECT 'A' col1, 'AA' col2 FROM dual UNION ALL
SELECT 'B' col1, 'BA' col2 FROM dual UNION ALL
SELECT 'C' col1, 'AC' col2 FROM dual UNION ALL
SELECT 'D' col1, 'DD' col2 FROM dual)
SELECT 1 case_no, -- case 1: no rows expected to be returned (no t1 rows with an id between 6 and 10)
t1.*,
t2.*
FROM t1
CROSS JOIN t2
WHERE t1.id BETWEEN 6 AND 10
AND t2.col2 LIKE 'A%'
UNION ALL
SELECT 2 case_no, -- case 2: no rows expected to be returned (no t2 rows with a col2 starting with "C")
t1.*,
t2.*
FROM t1
CROSS JOIN t2
WHERE t1.id BETWEEN 2 AND 4
AND t2.col2 LIKE 'C%'
UNION ALL
SELECT 3 case_no, -- case 3: no rows expected to be returned (no t1 rows with an id between 6 and 10, and no t2 rows with a col2 starting with "C")
t1.*,
t2.*
FROM t1
CROSS JOIN t2
WHERE t1.id BETWEEN 6 AND 10
AND t2.col2 LIKE 'C%'
UNION ALL
SELECT 4 case_no, -- case 4: 6 rows expected to be returned (3 t1 rows with an id between 2 and 4, and 2 t2 rows with a col2 starting with "A"; 3 x 2 = 6)
t1.*,
t2.*
FROM t1
CROSS JOIN t2
WHERE t1.id BETWEEN 2 AND 4
AND t2.col2 LIKE 'A%';
CASE_NO ID VAL COL1 COL2
---------- ---------- ---------- ---- ----
4 2 20 A AA
4 3 30 A AA
4 4 40 A AA
4 2 20 C AC
4 3 30 C AC
4 4 40 C AC
You can see that only case 4 (rows in both tables match the predicates) has any rows returned by the cross join.
ETA: if you were wanting to see employee rows regardless of whether there are matching date rows or not, you would need to use an outer join, e.g. using my earlier example, case 2 would become:
WITH t1 AS (SELECT 1 ID, 10 val FROM dual UNION ALL
SELECT 2 ID, 20 val FROM dual UNION ALL
SELECT 3 ID, 30 val FROM dual UNION ALL
SELECT 4 ID, 40 val FROM dual UNION ALL
SELECT 5 ID, 50 val FROM dual),
t2 AS (SELECT 'A' col1, 'AA' col2 FROM dual UNION ALL
SELECT 'B' col1, 'BA' col2 FROM dual UNION ALL
SELECT 'C' col1, 'AC' col2 FROM dual UNION ALL
SELECT 'D' col1, 'DD' col2 FROM dual)
SELECT t1.*,
t2.*
FROM t1
LEFT OUTER JOIN t2 ON t2.col2 LIKE 'C%'
WHERE t1.id BETWEEN 2 AND 4;
ID VAL COL1 COL2
---------- ---------- ---- ----
2 20
3 30
4 40
I have the following values in my table
A B
1 2
2 3
4 5
2 1
5 6
7 6
6 5
what a sql query in order to find the results which have a pair so this is the output is
1 2
2 1
5 6
6 5
Seems like there're already great solutions:
SELECT t.A, t.B FROM table AS t1 INNER JOIN table AS t2 ON t1.A = t2.B AND t1.B = t2.A
WITH CTE(A,B) AS
(
SELECT 1, 2 UNION ALL
SELECT 2, 3 UNION ALL
SELECT 4, 5 UNION ALL
SELECT 2 ,1 UNION ALL
SELECT 5, 6 UNION ALL
SELECT 7, 6 UNION ALL
SELECT 6 ,5
)
SELECT C.A,C.B
FROM CTE AS C
JOIN CTE AS C2 ON C.A=C2.B AND C.B=C2.A
This is another way to do it. With Self join
SELECT t1.*
FROM table1 t1
table1 t2 ON t1.a = t2.b AND t2.a = t1.b
Doing an Inner join will help you in this case:
SELECT t.col1, t.col2
FROM Tablename t
INNER JOIN Tablename t2
ON t.col1 = t2.col2 AND t.col2 = t2.col1
This will give you the required result:
Sample Output :
Innings
Totalplayer
2
1
1
2
6
5
5
6
View on DB Fiddle
Table 1
no name col1
1 a a_1
2 b b_1
Table 2
id name parent
a_1 zz c_1
b_1 yy d_1
c_1 aa null
d_1 bb e_1
e_1 dd1 null
what i want to show is showing the all list name. for example table 1 name a has col1 name a_1 it will show the name on table 2, and then check the parent in the table 2 and show it and keep checking until it found null. the example is like below.. im sorry for my bad explanation
t1_name t2_name t2_name t2_name
a zz aa
b yy bb dd1
or shows like below
t1_name t2_name
a aa/zz
b dd1/bb/yy
what I've done is this query
select t1.name,t2.name as folder from table1 as t1 inner join table2 as t2 on t1.col1=t2.id
and I don't know how to check again in query... I am using oracle version 12.2.0.1.0 in SQL developer any help?
You want to get the rows from the first table and then recursively fetch all the rows from the second table until you reach a null parent, so you do:
with cte(NAME,
PARENT,
CURRENTPATH) as
(select t1.NAME,
t2.PARENT,
t2.NAME as CURRENTPATH
from TABLE1 t1
join TABLE2 t2 on t1.COL1 = t2.ID
union all
select t1.NAME,
t2.PARENT,
t1.CURRENTPATH || '/' || t2.NAME as CURRENTPATH
from cte t1
join TABLE2 t2 on t2.ID = t1.PARENT)
select NAME,
CURRENTPATH
from cte
where PARENT is null;
You can use the hierarchical query as following:
SQL> -- Your data
SQL> with table1(no,name,col1) as
2 (SELECT 1, 'a','a_1' FROM DUAL UNION ALL
3 SELECT 2, 'b','b_1' FROM DUAL
4 ),
5 table2 (id, name, parent) as
6 (select 'a_1', 'zz', 'c_1' from dual union all
7 select 'b_1', 'yy', 'd_1' from dual union all
8 select 'c_1', 'aa', null from dual union all
9 select 'd_1', 'bb', 'e_1' from dual union all
10 select 'e_1', 'dd1', null from dual)
11 -- Your query starts from here
12 SELECT
13 T1.NAME AS T1_NAME,
14 T2.NAMES AS T2_NAMES
15 FROM TABLE1 T1
16 JOIN (
17 SELECT
18 T2.ID,
19 SYS_CONNECT_BY_PATH(T2.NAME, '/') AS NAMES,
20 ROW_NUMBER() OVER(PARTITION BY ID ORDER BY LEVEL DESC) AS L
21 FROM TABLE2 T2
22 CONNECT BY T2.PARENT = PRIOR T2.ID
23 ) T2 ON T1.COL1 = T2.ID
24 WHERE L = 1;
T1_NAME T2_NAMES
------- ---------------
a /aa/zz
b /dd1/bb/yy
SQL>
Cheers!!
Which Oracle version are you using?
I want to categorize data into two types based on:
If a value exists in T2, display "A", else display "B" as "Type". Is there a way to implement this in case when or decode?
T1 is the parent of T2.
T1
1
2
3
4
5
T2
1
1
3
3
3
4
Ideally my output would be
Type
A
B
A
A
B
edit: I want to add that A and B are text values I want to display based on my above condition, this is not coming from the db. Also, T2 will not have a corresponding record at all for 2 & 5. so I cannot really check for null.
Try this:
SELECT T1.Col,
CASE WHEN T2.Col IS NOT NULL THEN 'A' ELSE 'B' END AS Type
FROM T1
LEFT JOIN (
SELECT DISTINCT Col FROM T2
) AS T2 ON T1.Col = T2.Col
Oracle Setup:
CREATE TABLE T1 ( column_name ) AS
SELECT LEVEL FROM DUAL CONNECT BY LEVEL < 6;
CREATE TABLE t2 ( column_name ) AS
SELECT 1 FROM DUAL UNION ALL
SELECT 1 FROM DUAL UNION ALL
SELECT 3 FROM DUAL UNION ALL
SELECT 3 FROM DUAL UNION ALL
SELECT 4 FROM DUAL;
Query:
SELECT NVL2( T2.column_name, 'A', 'B' ) AS Type
FROM T1
LEFT OUTER JOIN
( SELECT DISTINCT column_name FROM T2 ) T2
ON T1.column_name = T2.column_name
ORDER BY T1.column_name;
Output:
TYPE
----
A
B
A
A
B
I'm having trouble crafting an Oracle SQL query that returns the results I seek. It's possible that what I'm trying to do isn't possible.
For a given code in table one, if the code exists in table two and ANY of the flags are "1", then the status should be "1" in the query results. Otherwise, the status should be "0". If the code doesn't exist at all in table 2, then the status should be null.
tab1
------------
id,code
------------
1,ABC
2,DEF
3,GHI
4,JKL
5,MNO
6,PQR
7,STU
tab2
------------
id,code,flag
------------
1,ABC,0
2,ABC,0
3,DEF,1
4,DEF,1
5,GHI,0
6,GHI,1
7,JKL,1
8,JKL,0
9,MNO,0
10,PQR,1
(query?)
result
------------
id,code,status
------------
1,ABC,0
2,DEF,1
3,GHI,1
4,JKL,1
5,MNO,0
6,PQR,1
7,STU,null
So far, the only query I've been able to come up with is this, which doesn't give the right results in the status column...
select tab1.*, (select * from (
select flag from tab2 where tab2.code = code order by flag desc)
where rownum <=1) as status from tab1;
... status is always "1", which is incorrect.
I'm thinking that instead of using order by and selecting the first result, it might be possible to instead count the number of "1" flags for each code, but I'm not sure if that would work.
My first inclination is to use a subselect:
select t1.*,
(select max(t2.flag)
from table2 t2
where t2.code = t1.code
) as t2flag
from table1 t1;
You can also phrase this as a left join with an aggregation:
select t1.*, t2.flag
(select max(t2.flag)
from table2 t2
where t2.code = t1.code
) as t2flag
from table1 t1 left join
(select t2.code, max(t2.flag) as flag
from table2 t2
group by t2.code
) t2
on t2.code = t1.code;
Both these methods are assuming that flag is either 0 or 1, as in your question.
I'd use a LEFT JOIN:
select t1.id, max(t1.code) code, max(t2.flag) status
from table1 t1
left join table2 t2 on t1.code=t2.code
group by t1.id
Assuming that 0 and 1 are the only two flags, what about something like:
with tab1 as (select 1 id, 'ABC' code from dual union all
select 2 id, 'DEF' code from dual union all
select 3 id, 'GHI' code from dual union all
select 4 id, 'JKL' code from dual union all
select 5 id, 'MNO' code from dual union all
select 6 id, 'PQR' code from dual union all
select 7 id, 'STU' code from dual),
tab2 as (select 1 id, 'ABC' code, 0 flag from dual union all
select 2 id, 'ABC' code, 0 flag from dual union all
select 3 id, 'DEF' code, 1 flag from dual union all
select 4 id, 'DEF' code, 1 flag from dual union all
select 5 id, 'GHI' code, 0 flag from dual union all
select 6 id, 'GHI' code, 1 flag from dual union all
select 7 id, 'JKL' code, 1 flag from dual union all
select 8 id, 'JKL' code, 0 flag from dual union all
select 9 id, 'MNO' code, 0 flag from dual union all
select 10 id, 'PQR' code, 1 flag from dual)
select t1.id,
t1.code,
t2.flag status
from tab1 t1
left join (select code,
max(flag) flag
from tab2
group by code) t2
on (t1.code = t2.code);
ID CODE STATUS
---------- ---- ----------
5 MNO 0
6 PQR 1
2 DEF 1
1 ABC 0
3 GHI 1
4 JKL 1
7 STU
Maybe I'm missing something, but it seems to be as simple as this:
select tab1.id, tab1.code, max(tab2.flag) status
from tab1
left join tab2 on tab1.code = tab2.code
group by tab1.id, tab1.code
order by tab1.id;
A sample SQL Fiddle gives the desired result:
| id | code | status |
|----|------|--------|
| 1 | ABC | 0 |
| 2 | DEF | 1 |
| 3 | GHI | 1 |
| 4 | JKL | 1 |
| 5 | MNO | 0 |
| 6 | PQR | 1 |
| 7 | STU | (null) |
SELECT ID,
CODE,
MAX( STATUS)
FROM
(SELECT DISTINCT T1.ID,
T1.CODE,
FLAG AS STATUS
FROM T1
LEFT JOIN T2
ON T1.CODE = T2.CODE
)
GROUP BY ID,
CODE;
This gives result as you asked:
SELECT tab1.id,tab1.code,max(tab2.flag) as Status
FROM tab1 LEFT JOIN tab2
ON tab1.code=tab2.code
GROUP BY tab2.code
ORDER BY tab1.id;