I have two tables. Both contains question id field. I want to get all records from first table that are not present in second one. I don't want to use "NOT IN" constrain as second table having more than 400000 records.
Try something like
SELECt t1.*
FROM Table1 t1 LEFT JOIN
Table2 t2 ON t1.questionID = t2.questionID
WHERE t2.questionID IS NULL
Typically you would do this using a LEFT JOIN combined with a WHERE clause selecting every row where the joined table returns no results.
SELECT t1.*
FROM Table1 t1
LEFT OUTER JOIN Table2 t2 ON t2.ID = t1.ID
WHERE t2.ID IS NULL
try:
select from t1
right join t2 on t2.id = t1.id where t2.id is null
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;
I'm trying to search a rows of table3 that have id match in a table1 OR table2 with this query
SELECT T1.*, T3.*,T2.*
FROM (
select id
from table1
where condition like '%field%') T1
inner join table3 T3
ON T3.id=T1.id
left join (
select id
from table2
where condition like '%field%') T2
ON T3.id=T2.id
If in table T1 have matches but in table2 not, the query works fine but if in table1 not have matches but have in table2 the query not show any results.
Someone can help me?
Thanks
do left join to avoid excluding rows, and add a where with the condition you need FOr readability sake,avoid right joins and jsut use proper table order
SELECT T1.*, T3.*,T2.*
FROM Table3 T3
left join (
select id
from table1
where condition like '%field%') T1
ON T3.id=T1.id
left join (
select id
from table2
where condition like '%field%') T2
ON T3.id=T2.id
where t3.id is not null or t2.id is not null
I have two tables. The first table contains ID, First_Name and Last_Name.
The 2nd table contains two foreign key fields containing different ID's of the first table.
I want to be able to run a SQL query that gets reults of the 2nd table which then grabs the First_Name of each member based on the two different foreign keys.
How would I go about doing this?
select t2.*, t1a.firstname, t1b.firstname
from table2 t2
left join table1 t1a on t2.fk1 = t1a.id
left join table1 t1b on t2.fk2 = t1b.id
Suppose the second table has fields as such
userid, supervisorid ( both referring to the Id column of the first table )
you may write join to get the value like this
SELECT t2.*, ID, firstname, lastname FROM table 2 t2
LEFT OUTER JOIN table 1 t1 ON
t2.userid = t1.id
OR t2.supervisorid = t1.id
I think correct sql would be below one using OR condition in outer join or using union
SELECT t1.id,t1.name from table1 t1, table2 t2 WHERE t1.id1 = t2.id1
UNION
SELECT t1.id,t1.name from table1 t1, table2 t2 WHERE t1.id1 = t2.id0
SELECT t1.id, t1.name from table2 t2 LEFT OUTER JOIN table1 t2 ON t1.id = t2.id or t1.id1 = t2.id0
If I have
SELECT * FROM Table1 t1
LEFT JOIN Table2 t2 ON t1.id = t2.id
WHERE t1.user='bob';
Does the WHERE clause run after the two tables are JOINED?
How do I make it so it runs prior to the JOIN?
The where clause will be executed before the join so that it doesn't join unnecessary records. So your code is fine the way it is.
Change the WHERE to another JOIN condition
LEFT JOIN Table2 t2 on t1.id = t2.id AND t1.user='bob'
In my experience in a left join you cannot exclude records in the 'left' (t1) table in the ON-statement since - by definition - all t1 records will be included. The where statement does work as it will be applied to the result of the join afterwards.
I do not exactly know what you want to achieve but most probably an inner join suits your needs as well and then you can add the t1.user='bob' condition to the ON-statement.
But if Mosty Mostacho is correct, the location (WHERE vs ON) of the condition is not relevant for speed of execution.
You should just add t1.user='bob' condition to ON clause before other condition and it will be evaluated first:
SELECT * FROM Table1 t1
LEFT JOIN Table2 t2
ON t1.user='bob' AND t1.id = t2.id;
What you may use is table expression after FROM like this:
SELECT *
FROM (SELECT
id
FROM Table1
WHERE user = 'bob') AS t1
LEFT JOIN Table2 t2
ON t1.id = t2.id
you can do
SELECT *
FROM Table1 t1
LEFT JOIN Table2 t2
ON t1.id=t2.id AND t1.user='bob';
RIGHT JOIN was the solution:
SELECT cars.manufacturer, cars.year FROM cars
RIGHT JOIN (SELECT m.manufacturer FROM cars AS m ORDER BY m.year DESC LIMIT 3) subq
ON cars.manufacturer=subq.manufacturer
Haven't put it through the full rigors yet, but seems to work.