I have table1 like this:
and other column in table2 having two unique value 3 and 4.
How do I write a query to make a table like
Actually My table is more complicated than the one above:
I tried :
"Select DISTINCT table1.x, table1.y ,table2.z from table1 Where table1.a = "something'
and table1.b is Not Null,
CROSS JOIN table2 Where table2.z='something' OR table2.z='something2' "
it does not work...I am using a modeling package which use the sql language and I am not sure it is fully compatible with sql.
You are looking to find the Cartesian product of two tables. It can be short as:
select * from table1, table2;
Or explicitly using a cross join as:
select table1.*, table2.*
from table1 cross join table2;
To filter each table individually, you can use sub-queries:
select distinct table1.x, table1.y, table2.z
from (select * from table1
where table1.a = 'something' and table1.b is not NULL
) as table1
cross join (select * from table2
where table2.z = 'something' or table2.z = 'something2'
) as table2;
Or use combine the logic under one query:
select distinct table1.x, table1.y, table2.z
from table1, table2
where table1.a = 'something' and table1.b is not NULL
and (table2.z = 'something' or table2.z = 'something2')
Related
i want create a sql statemnt (in PL SQL Developer) with a join with comma seperated?
SELECT * FROM TABLE1 t1 JOIN TABLE2 t2 ON t1.tab_id, second_id = t2.tab_id, second_id;
I always get a ORA-00920 Exception. If i change it to two Rows:
t1.tab_id = t2.tab_id AND t1.second_id = t2.second_id;
Then i get rows.
Can some say me if i can use the first step with coma seperated columns?
Greetz
You need a valid condition:
SELECT *
FROM TABLE1 t1 JOIN
TABLE2 t2
ON t1.tab_id = t2.tab_id AND t1.second_id = t2.second_id;
I think Oracle will also let you do:
SELECT *
FROM TABLE1 t1 JOIN
TABLE2 t2
ON (t1.tab_id, t1.second_id) in ( (t2.tab_id, t2.second_id) );
Or even:
SELECT *
FROM TABLE1 t1 JOIN
TABLE2 t2
USING (tab_id, second_id);
This works because the JOIN keys have the same names in the two tables.
select *
from table1 t1,
table2 t2,
table3 t3
where t2.parent_id = t1.row_id
and t2.xyz is not null
and (
select count(*)
from table3
where xyz = t2.row_id
) = 0;
Will it work?
I am using the alias t2 within my subquery.
My requirement is to check is to specify condition in where clause such that there is no record present in table3 where column xyz of table3 is stored as row_id of table2.
You can use NOT EXISTS to assert that there is no row returned from the subquery. Use modern explicit join syntax instead of comma based legacy syntax. No need to join table3 outside (you were making a cross join effectively).
select *
from table1 t1
join table2 t2 on t2.parent_id = t1.row_id
where t2.xyz is not null
and not exists (
select 1
from table3
where xyz = t2.row_id
);
there are two tables TABLE1 and TABLE2 in TABLE1 there are records which does not exist in TABLE2 with left join below i wanted to query all records which are in TABLE1 if the record does not exist in table2 however.
Note: about WHERE class in my code that is required this is because, there can be several records in the name of 'IN PROGRESS' in TABLE2 with one record in the name of 'GRADUATED' i wanted to distinct records based on table 1 ID that if there is any record in the name of 'GRADUATE' it should show only that else it should show inprogress.
SELECT DISTINCT
TABLE1.ID,
TABLE2.TRAINING_STATUS_CHECK
FROM TABLE1
LEFT JOIN TABLE2
ON TABLE1.ID = TABLE2.FK_ID_CLASS
WHERE NOT EXISTS
(
SELECT DISTINCT
TABLE1.ID,
TABLE2.TRAINING_STATUS_CHECK
FROM TABLE1
LEFT JOIN TABLE2
ON TABLE1.ID = TABLE2.FK_ID_CLASS
WHERE TABLE2.TRAINING_STATUS_CHECK = 'GRADUATED')
OR TABLE2.TRAINING_STATUS_CHECK = 'GRADUATED'
I see some odds with your query:
exists part are not related with you main query. I think you need some relation
distinct in part not exists are not needed
You filter columns with the same conditions as filter main row set
As I understand you want to get all rows from table1 with state 'GRADUATED' int table2 and any row from table1 where rows in table2 are not exists or state not equal 'GRADUATED'
SELECT DISTINCT
t1.ID,
t2.TRAINING_STATUS_CHECK
FROM TABLE1 t1
LEFT JOIN TABLE2 t2 ON t1.ID = t2.FK_ID_CLASS
WHERE NOT EXISTS
(
SELECT NULL /*its not nesessary what you need*/
FROM TABLE1 sub_t1
JOIN TABLE2 sub_t2 ON sub_t1.ID = sub_t2.FK_ID_CLASS /* left join replaced to inner */
WHERE sub_t2.TRAINING_STATUS_CHECK = 'GRADUATED'
AND sub_t1.ID = t1.ID /*relation with outer query*/
)
OR t2.TRAINING_STATUS_CHECK = 'GRADUATED'
where the relatonship between tables does not exist - but only if the comparison involves rows in table that are not 'graduated' (I think)
SELECT DISTINCT
TABLE1.ID,
TABLE2.TRAINING_STATUS_CHECK
FROM TABLE1
LEFT JOIN TABLE2 ON TABLE1.ID = TABLE2.FK_ID_CLASS
AND TABLE2.TRAINING_STATUS_CHECK <> 'GRADUATED'
WHERE TABLE2.FK_ID_CLASS IS NULL
Not sure about your question but if you want all the records from table 1 who are not in table 2, you just have to do this :
SELECT TABLE1.ID
FROM TABLE1
LEFT JOIN TABLE2 ON TABLE1.ID = TABLE2.FK_ID_CLASS
WHERE TABLE2.FK_ID_CLASS IS NULL
Try this:
SELECT DISTINCT TABLE1.ID, TABLE2.TRAINING_STATUS_CHECK
FROM TABLE1
LEFT JOIN TABLE2
ON TABLE1.ID = TABLE2.FK_ID_CLASS
AND (NOT EXISTS (SELECT 1
FROM TABLE2 t
WHERE TABLE1.ID = t.FK_ID_CLASS
AND t.TRAINING_STATUS_CHECK = 'GRADUATED')
OR TABLE2.TRAINING_STATUS_CHECK = 'GRADUATED')
For the record, conditions on the right table of a LEFT JOIN need to be placed inside the ON() clause or the join will transfer into an INNER JOIN due to NULL comparison.
It seems to me you have three distinct cases that can be "ORed together" using UNION; personally I find keeping all three separated like this makes things much easier to read and understand:
--- ID with GRADUATED exists in TABLE2
( SELECT ID, 'GRADUATED' AS TRAINING_STATUS_CHECK
FROM TABLE1
INTERSECT
SELECT FK_ID_CLASS, 'GRADUATED'
FROM TABLE2
WHERE TRAINING_STATUS_CHECK = 'GRADUATED' )
UNION
--- ID without GRADUATED exists in TABLE2
( SELECT ID, 'IN PROGRESS'
FROM TABLE1
MINUS
SELECT FK_ID_CLASS, 'IN PROGRESS'
FROM TABLE2
WHERE TRAINING_STATUS_CHECK = 'GRADUATED' )
UNION
--- ID does not exist in TABLE2
( SELECT ID, '{{NONE}}'
FROM TABLE1
WHERE ID NOT IN ( SELECT FK_ID_CLASS FROM TABLE2 ) );
I want to cross join the two table
Query
Select * from table1 cross join select * from table2
Above query is showing error.
What wrong in my query
Reference
The result set of the Cross Join is the number of rows in the first table multiplied by the number of rows in the second table
SELECT T1.Columns1, T1.Column2, T2.ColumnName FROM Table1 T1
CROSS JOIN Table2 t2
You must use select like this : SELECT T1.FIELD1, T2.FIELD2 FROM TABLE1 AS T1 CROSS JOIN TABLE2 AS T2 - FIELD[X] FOR EXAMPLE ONLY
Try this:
SELECT * FROM table1, table2
or this:
select * from table1 CROSS JOIN table2;
I have this slow query
select * from table1 where id NOT IN ( select id from table2 )
Would this be faster by doing something like (not sure if this is possible):
select * from table1 where id not in ( select id from table2 where id = table1.id )
Or:
select * from table1 where table1.id NOT EXIST( select id from table2 where table2.id = table1.id )
Or:
select * from table1
left join table2 on table2.id = table1.id
WHERE table2.id is null
Or do something else? Like break it up into two queries ...
The question is - are the field(s) in the comparison nullable (meaning, can the column value be NULL)?
If they're nullable...
...in MySQL the NOT IN or NOT EXISTS perform better - see this link.
If they are NOT nullable...
... LEFT JOIN / IS NULL performs better - see this link.
select table1.* from table1
LEFT JOIN table2 ON table1.id = table2.id
WHERE table2.id IS NULL
The object being to get rid of NOT IN