I am trying to find the rows that all four tables share in common.
I tried using this:
SELECT *
FROM TABLE1
INTERSECT
SELECT *
FROM TABLE2
INTERSECT
SELECT *
FROM TABLE3
INTERSECT
SELECT *
FROM TABLE4;
But got no results, i know there are rows that meet this requirement. Because using union instead and adding "order by" i see four rows with the same description from different tables.
Use INNER JOIN with conditions on the fields that you want
ex:
SELECT
t1.*
FROM
TABLE1 t1
INNER JOIN TABLE2 t2
ON t1.field1 = t2.field1
AND t1.field2 = t2.field2
...
INNER JOIN TABLE2 t3
ON t1.field1 = t3.field1
AND t1.field2 = t3.field2
...
Related
I basically want to join the result of two INNER JOINs.
On this scheme I want to get the three arrows results combined.
I've tried INNER / LEFT combinations but it doesn't do the trick.
I think a nested request could be the solution but how ?
Thanks
The answer was actually simple : UNION
SELECT t1.*
FROM
(SELECT t1.*
FROM table1 t1 JOIN table2 t2 ON t2.id = i.client_id
UNION
SELECT t1.*
FROM t1 t1 JOIN table3 t3 ON t1.id = t3.client_id) as q1
;
I'd use logic to express the condition T1.id exists in T2 or T3 more directly, and certainly avoid use of DISTINCT or UNION.
Options could be to use EXISTS directly (As this is immure to the possibility of duplication cause by 1:many joins)...
SELECT
t1.*
FROM
table1 t1
WHERE
EXISTS (SELECT * FROM table2 t2 WHERE t2.t1_id = t1.id)
OR
EXISTS (SELECT * FROM table3 t3 WHERE t3.t1_id = t1.id)
Or to LEFT JOIN twice and then exclude unwanted rows. (This assumes that the joins are never 1:many, which would introduce duplication, and the unwanted need for a DISTINCT.)
SELECT
t1.*
FROM
table1 t1
LEFT JOIN
table2 t2
ON t1.id = t2.t1_id
LEFT JOIN
table3 t3
ON t1.id = t3.t1_id
WHERE
t2.t1_id IS NOT NULL
OR
t3.t1_id IS NOT NULL
I have 2 tables, one is table1
and another is table 2
I want the result by a query, like
I have tried select id from table2 order by (select id from table1); but it is giving error.
You can join and sort. But you need a column that defines the ordering of the rows in table1. Let me assume that you have such column, and that is is called ordering_id.
select t2.*
from table2 t2
inner join table1 t1 on t1.id = t2.id
order by t1.ordering_id
You can even use a subquery in the order by clause:
select *
from table2 t2
order by (select t1.ordering_id from table1 t1 where t1.id = t2.id)
Join the two tables and then order the result.But for that you need to have some column for ordering and this does not seems to be the case. Syntax you are using for ordering will not work.
SELECT A.ID, B.NAME FROM TABLE1 A INNER JOIN TABLE2 B
ON(A.ID = B.ID) ORDER BY A.ID DESC
finally got the answer
select t2.*
from table2 t2
inner join table1 t1 on t1.id = t2.id;
Is it possible to OR two separate INNER JOIN's so that the result set contains data from either of the two INNER JOIN's? For instance, is the following possible in MySQL.
SELECT * FROM table1
(INNER JOIN table2 ON table1.column_name=table2.column_name)
OR
(INNER JOIN table3 ON table1.column_name=table3.column_name)
No you cant do this way, one way is to use union
SELECT * FROM table1 INNER JOIN table2 ON table1.column_name=table2.column_name
union
SELECT * FROM table1 INNER JOIN table3 ON table1.column_name=table3.column_name
You can use UNION:
SELECT * FROM table1 INNER JOIN table2 ON table1.column_name=table2.column_name
UNION DISTINCT
SELECT * FROM table1 INNER JOIN table3 ON table1.column_name=table3.column_name
As described at https://dev.mysql.com/doc/refman/4.1/en/union.html, UNION combines the results of several selects.
you need use where
select * from table1
where
(table1.column_name = (select table2.column_name from table2 inner join table1.column_name as on table1.column_name = table2.column_name))
OR
(table1.column_name = (select table3.column_name from table3 inner join table1.column_name as on table1.column_name = table3.column_name))
work perfect here!
Is is possible to simplify this UNION to avoid the near redundancy of the queries being unioned? As seen here, both queries are similar. They just join on a different column in table2. The reason i use Union, instead of just Inner Joining 2x in the same query is because the results must be in 1 column by virtue of the fact that this queries is used as a subquery.
SELECT t1.id as id
FROM table1 g
INNER JOIN table2 t1 on g.t_id = t1.id
WHERE g.id=1
UNION
SELECT t2.id as id2
FROM table1 g
INNER JOIN table2 t2 on g.t2_id = t2.id
WHERE g.id=1
I don't see why this couldn't be treated as a simple inner join that can be satisfied by a match in either of two predicates. I've removed the original table aliases of t1, t2, and g for the sake of clarity. Since I don't know if the query could produce duplicate rows, I used DISTINCT in order to collapse duplicate rows in the same manner that the UNION did in the original query.
SELECT DISTINCT table2.id
FROM table1
INNER JOIN table2
ON ( table1.t_id = table2.id OR table1.t2_id = table2.id )
WHERE table1.id = 1
;
It is possible to do with two joins, and the IFNULL() function:
SELECT IFNULL (t1.id, t2.id) as id
FROM table1 g
INNER JOIN table2 t1 on g.t_id = t1.id
INNER JOIN table2 t2 on g.t2_id = t2.id
WHERE g.id=1
You might find this simpler:
select distinct t.id
from table2 t
where t.id in (select g.t_id from table1 g) or
t.id in (select g.t2_id from table1 g)
However, the performance would be awful on MySQL. You can also do:
select distinct t.id
from table2 t
where exists (select 1 from table1 g where g.t_id = t.id or g.t2_id = t.id)
The second version should work better in MySQL.
I am joining 2 tables -tbl1 and tbl2. Left join give all data from tbl1 which is in tbl2 or only on tbl1. Right join gives data from tbl2 which is don't exists in tbl1.
I want to combine both results.
What is the best way to do this so that I get all data from tbl1 and tbl2?
The only you can do that is by using UNION. MySQL doesn't support FULL JOINjust like in MSSQL.
SELECT *
FROM tbl1 t1
LEFT JOIN tbl2 t2
ON t1.col = t2.col
UNION
SELECT *
FROM tbl1 t1
RIGHT JOIN tbl2 t2
ON t1.col>= t2.<col
SEE HERE: Simulating FULL JOIN in MYSQL
By the way, UNION has optional keyword ALL,when the ALL is omitted, UNION automatically selects DISTINCT rows from the resultset.
EXAMLE:
SELECT *
FROM tableA
UNION ALL
SELECT *
FROM tableA
this can result duplicates rows
ColA ColB
==================
1 John
2 Jade
2 Jade
3 Hello
BUT if you omit the word ALL
SELECT *
FROM tableA
UNION
SELECT *
FROM tableA
this can result distinct rows only
ColA ColB
==================
1 John
2 Jade
3 Hello
What you want is FULL JOIN
LEFT JOIN + RIGHT JOIN = FULL JOIN
So try this:
SELECT * FROM tbl1
LEFT JOIN tbl2 ON tbl1.id = tbl2.id
UNION
SELECT * FROM tbl1
RIGHT JOIN tbl2 ON tbl1.id = tbl2.id
The UNION clause combines the results of two SQL queries into a single table of all matching rows.
Here's an alternative that can be easily extended if you have a full join of more than 2 tables:
SELECT t1*, t2.*
FROM
( SELECT col
FROM tbl1
UNION
SELECT col
FROM tbl2
) AS d
LEFT JOIN tbl1 AS t1
ON t1.col = d.col
LEFT JOIN tbl2 AS t2
ON t2.col = d.col ;
you have to use FULL OUTER JOIN, But mysql doesnt support it.. You could do this for getting the result:
SELECT *
FROM tbl1 t1 LEFT JOIN tbl2 t2
ON t1.<col> = t2.<col>
UNION
SELECT *
FROM tbl1 t1 RIGHT JOIN tbl2 t2
ON t1.<col>= t2.<col>