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I have generated the following sql query code in access using the Qbe and converting it to sql.However, i want proof that i did without help so i intend to take out all inner join statements and replace them with the WHERE statement. How do i work it ...
Started by Selase on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
Here's your queryIt's a strange thing to want to do (as commenters say, INNER JOIN is usually better, and applying a mechanical transformation proves nothing....
That is the weirdest JOIN statement I've seen to date.
Cond1 and cond2 might be.
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I would like to know if there's a really performance gain between those two options :
Option 1 :
I do a SQL Query with a join to select all User and their Ranks. Option 2 :
I do one SQL Query to select all User I fetch all user and do another SQL Query...
Started by Melursus on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
Use the join if you....
(e.g., separate queries, but the second query gets used only occasionally).
However, if your first result-loading of ranks.
Will have to do an extra query with a network round trip for each join.
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I have two tables:
Patient
pkPatientId FirstName Surname PatientStatus
pkPatientStatusId fkPatientId StatusCode StartDate EndDate Patient -> PatientStatus is a one to many relationship.
I am wondering if its possible in SQL to do a join which returns...
Answer Snippets (Read the full thread at stackoverflow):
BY ps.fkPatientId, ps.StartDate) as rownumber FROM Patient p INNER JOIN PatientStatus ps, ps.StatusCode, ps.StartDate, ps.EndDate FROM Patient p INNER JOIN PatientStatus ps ON p.pkPatientId, ps.StartDate, ps.EndDate FROM Patient p INNER....
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Ask your Facebook Friends
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I have my business-logic in ~3000 lines of T-SQL stored procedures, and most of them has next approach:
SELECT A.A, B.B, C.C FROM aaa AS A, bbb AS B, ccc AS C -- here is what I called multi-table WHERE A.B = B.ID AND B.C = C.ID AND C.ID = @param
Will ...
Started by abatishchev on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
The two queries are equal - the first is using non-ANSI JOIN....
They should be equal.
With this particular query, but there are a few circumstances where the older outer join syntaxExecute both and check their query plans.
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Hi, guys, how or where is the "join" query in Django?
i think that Django dont have "join"..but how ill make join?
Thanks
Started by Asinox on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
SQL Join queries are a hack because.
Look into model relationships and accessing related objects.
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Are there any performance issues if an sql query contains lot of joins?
Started by jayaprakashbr on
, 6 posts
by 6 people.
Answer Snippets (Read the full thread at stackoverflow):
Read more in this article
Performance....
join book on book.bookid=chapter.bookid where chapter.subject='penguins'
The query would probably readOne of the best ways to boost JOIN performance is to limit how many rows need to be JOINed.
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Hi is it possible to convert this sub query to a join ?
SELECT staff_no FROM doctor WHERE NOT EXISTS (SELECT * FROM patient WHERE staff_no = consultant_no);
Started by Ben on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
LEFT JOIN....
NOT EXISTS vs.
See this article in my blog for comparison of three methods to do this query in MySQL :
NOT IN vs.
SELECT staff_no FROM doctor LEFT JOIN patient ON staff_no = consultant_no WHERE consultant in your WHERE clause.
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In general what makes an SQL query optimiser decide between a nested loop and a hash join.
Started by cindi on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
For a query like this:
SELECT * FROM a JOIN b ON b.b1 = a.a1 WHERE = condition in the ON clause)
HASH JOIN is the fastest method if all (or almost all) records should from a and uses the value....
Be used to limit the number of records.
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Can someone help me understand what's wrong with this query:
DELETE FROM noteproject INNER JOIN note ON noteproject.noteID = note.noteID INNER JOIN person ON note.personID = person.personID WHERE noteID = '#attributes.noteID#' AND personID = '#attributes...
Started by nobosh on
, 6 posts
by 6 people.
Answer Snippets (Read the full thread at stackoverflow):
I have no db at the moment to test what I'm tables that are used only for searching:
1)... .
Alternatively, you can write:
DELETE FROM noteproject USING noteproject INNER JOIN ...
Should be:
DELETE noteproject FROM noteproject INNER JOIN ...
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Hi, i'm trying to join 8 tables into one in order to create index used by other application, my query is like : (my mysql skill's very amateur)
SELECT t1_id, t2_name, t3_name, t4_name, t5_name, t6_name, t7_name, t8_name, t9_name FROM t1 LEFT JOIN t2 ON...
Started by lordlinier on
, 9 posts
by 9 people.
Answer Snippets (Read the full thread at stackoverflow):
But, first of all, you have indexes on all the fields used in the join? something like CREATE INDEX ix_t2_id on t2 (t2_id, t2_name t9_name from t9 where t1_id = t9_id) ....
It would help a bit if you could post the explain plan of the query.
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