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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):
Transformed into a WHERE as follows:
instead of each 2-way inner join A INNER JOIN B ON (cond1) WHERE ON es.entertainerid = e.entertainerid JOIN SPECIALITY s ON s.specialityid = es.specialityid WHERE e.entertainerid....
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Hi,
Let's say we have
SELECT * FROM A INNER JOIN B ON [....]
Assuming A has 2 rows and B contains 1M rows including 2 rows linked to A :
B will be scanned only once with "actual # of rows" of 2 right?
If I add a WHERE on table B :
SELECT * FROM A INNER...
Started by Mike Gleason jr Couturier on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
Or if your statistics are bad, there is no reason to... .
So it doesn't know that the join filter would pare B down to just two rows, it would do the WHERE is indexed but the join column is not, it will likely do the xyz filter first.
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I am trying to determine the performance of a piece of generated SQL that runs in SQL Server 2005.
It uses CROSS JOINS, but the conditionals tying the cross joined tables are in the where statement.
I previously thought that all cross joins that have ...
Started by jetimms on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
The Sql Optimiser is typically free to move restrictions between where clauses and 'on' clauses during join operations....
Contacts.id from companies cross join contacts where contacts.companyid = companies.id select for both queries.
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Hello, I develop against Oracle databases. When I need to manually write (not use an ORM like hibernate), I put join statements in the where clause sections.
for example (this is simplistic just to illustrate the style):
Select * from customers c, invoices...
Started by Jay on
, 11 posts
by 11 people.
Answer Snippets (Read the full thread at stackoverflow):
It supports LEFT, RIGHT, and FULL OUTER JOINs, which the WHERE....
Is the tendency to forget some join's WHERE clause, thereby resulting in a cartesian product the filtering WHERE conditions from the JOIN conditions.
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Query -
Select * FROM tbl1 LEFT OUTER JOIN tbl2 ON tbl1.id = tbl2.id AND tbl2.col2 = 'zyx' AND tbl2.col3 = 'abc' WHERE tbl1.col1 = 'pqr'
Here I'm doing left outer join and using 'and' along with join. (First I was using joins 'and' part in 'where' but...
Started by Rahuls on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
A couple of different ways to write this might be:
Add nulls to the where
Select * FROM tbl1 LEFT OUTER JOIN tbl2 ix_tbl2_2_3 ON tbl....
WHERE restricts the results so adding that effectively makes it an inner join.
JOIN.
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How can I replicate a LEFT OUTER JOIN in a WHERE clause? Essentially, I want to use a cross rather than a join in the FROM clause and then filter the second table accordingly: SELECT A.KEY, B.KEY FROM A, B WHERE ;
Note the key will not be null in either...
Started by David Beckman on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
Unless, of courseWhy....
????) ;
Assuming the column you want to join on is KEY from both tables,
SELECT A.KEY, B.KEY FROM A, B WHERE A.KEY of the cross join (which is what a WHERE clause is for), you won't get what you want.
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I am learning SQL and am trying to learn JOINs this week.
I have gotten to the level where I can do three table joins, similar to a lot of examples I've seen. I'm still trying to figure out the tiny details of how things work. All the examples I've seen...
Started by MedicineMan on
, 9 posts
by 9 people.
Answer Snippets (Read the full thread at stackoverflow):
The only ....
The same general logic applies when selecting the join type when you have multiples as with single join as you want.
It just depends on the data you are querying and what you are trying to follow .
An outer join in them.
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When joining to a subset of a table, any reason to prefer one of these formats over the other?
Subquery version:
SELECT ... FROM Customers AS c INNER JOIN (SELECT * FROM Classification WHERE CustomerType = 'Standard') AS cf ON c.TypeCode = cf.Code INNER...
Started by BradC on
, 11 posts
by 11 people.
Answer Snippets (Read the full thread at stackoverflow):
FROM Classification WHERE CustomerType = 'Standard') AS cf ON c.TypeCode = cf.Code INNER JOIN SalesReps ON c.TypeCode = cf.Code INNER JOIN SalesReps AS s ON cf.SalesRepID = s.SalesRepID WHERE WHERE CustomerType = ....
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Is there a difference in performance (in oracle) between
Select * from Table1 T1 Inner Join Table2 T2 On T1.ID = T2.ID
And
Select * from Table1 T1, Table2 T2 Where T1.ID = T2.ID
?
Started by Juan Manuel Formoso on
, 15 posts
by 15 people.
Answer Snippets (Read the full thread at stackoverflow):
However, as a coding practice, I would rather see the Join the join is better for describing exactly....
They should be exactly the same.
In the newer syntax.
Than the mixing of the join criteria with other needed where conditions.
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In SQL (MSSQL, Oracle, etc., whatever), when joining tables, what is the gain from adding a filter to the JOIN statement instead of having it in the WHERE clause?
i.e.
SELECT * FROM X INNER JOIN Y ON X.A = Y.A WHERE X.B = 'SOMETHING'
versus
SELECT * FROM...
Started by MasterMax1313 on
, 7 posts
by 7 people.
Answer Snippets (Read the full thread at stackoverflow):
For an INNER JOIN, I would not expect....
For INNER JOIN queries, the performance characteristics of these filters will depend ( JOIN clause) or after ( WHERE clause) the join is carried out.
In the where clause.
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