Joining two tables together within vb.net but getting the following error:
"Join expression not supported"
SELECT * FROM (General_Counters_Table AS a INNER JOIN Timers_Table AS b ON b.ulProductionTime = a.Product_ID) INNER JOIN Timers_Table AS b ON b.ulSetupTime = a.Product_ID
Product_ID exists in both General_Counters_Table and Timers_Table
The parser got confused when you join for a second time the Timers_Table because you use the same alias already used for the first join.
However it seems that you just want to produce a result with all fields from the A table and some fields from the B table. If this is the case you need
to join the two tables with the common field (Product_ID) and add, to the SELECT statement, the fields required from the A and B table
SELECT a.*, b.ulProductionTime, b.ulSetupTime, .......
FROM General_Counters_Table AS a
INNER JOIN Timers_Table AS b ON b.Product_ID = a.Product_ID
Related
I want to INNER JOIN some tables and then insert a condition where the entries of a table are dependant on another table (that was not joined with the others)
Something like this:
SELECT * FROM TABLE_A AS a
INNER JOIN TABLE_B AS b ON b.id_b=a.id_a
INNER JOIN TABLE_C AS c ON c.id_c=b.id_b
Now I want to add a condition (possibly a "WHERE" clause) that only selects the values in a field in TABLE_C that match another condition, the existence of a value in a field in TABLE_D
Possible statement:
WHERE c.code=d.another_code AND d.reg_number LIKE 999%
How do i declare in the query the TABLE_D, since I do not want to Join it with the others?
In other words, I want to intersect 3 sets (A,B,C) and the other one (set D) is intersected only with set C
The title of the question Run-time error '13': ... doesn't seem to match the content so I'll just answer the SQL part.
Maybe this is what you want?
SELECT * FROM TABLE_A AS a
INNER JOIN TABLE_B AS b ON b.id_b=a.id_a
INNER JOIN TABLE_C AS c ON c.id_c=b.id_b
WHERE c.code = -- or possiby IN instead of =
(SELECT another_code FROM TABLE_D WHERE another_code LIKE '999%')
If the subquery can return multiple rows you need to use WHERE c.code IN instead of WHERE c.code =
The most common type of join is: SQL INNER JOIN (simple join). An SQL INNER JOIN return all rows from multiple tables where the join condition is met.
This what W3Schools says about Inner Join. I was reading database management by Korth and one chapter in it was on relational algebra. In that, there was a Natural Join which, in my limited understanding, is the same as Inner Join.
Can someone please tell me if there is a difference between the two or they are different names of referring to the same thing.
A Natural Join is a form of Inner Join where the join is implicitly across all columns of matching names on both sides of the join.
E.g.
Table A
abc int
def int
ghi varchar(20)
Table B
abc int
def int
jkl int
A natural join between tables A and B would be the same as an inner join on columns abc and def.
Inner joins that could not be replaced with a Natural Join:
TableA
inner join
TableB
on
TableA.Column1 = TableB.Column2 --Column names don't match
or
TableA
inner join
TableB
on
TableA.Column1 >= TableB.Column1 --Not equality
Natural Join and Inner Join are not same commands.
Natural Join joins the tables on the basis of equality of values of common columns without typing the condition in query......while Inner join joins tables on the basis of condition specified in query which can be "=" or ">=" or "<="....
Natural Join :
tab1 NATURAL JOIN tab2;
this will automatically check for equality of values of common columns
Iner Join:
tab1 INNER JOIN tab2 ON (condition);
Moreover, NATURAL JOIN gives common column once in the output of query while INNER JOIN gives common columns of both tables
Can sombody Explains me about joins?
Inner join selects common data based on where condition.
Left outer join selects all data from left irrespective of common but takes common data from right table and vice versa for Right outer.
I know the basics but question stays when it comes to join for than 5, 8, 10 tables.
Suppose I have 10 tables to join. If I have inner join with the first 5 tables and now try to apply a left join with the 6th table, now how the query will work?
I mean to say now the result set of first 5 tables will be taken as left table and the 6th one will be considerded as Right table? Or only Fifth table will be considered as left and 6th as right? Please help me regarding this.
When joining multiple tables the output of each join logically forms a virtual table that goes into the next join.
So in the example in your question the composite result of joining the first 5 tables would be treated as the left hand table.
See Itzik Ben-Gan's Logical Query Processing Poster for more about this.
The virtual tables involved in the joins can be controlled by positioning the ON clause. For example
SELECT *
FROM T1
INNER JOIN T2
ON T2.C = T1.C
INNER JOIN T3
LEFT JOIN T4
ON T4.C = T3.C
ON T3.C = T2.C
is equivalent to (T1 Inner Join T2) Inner Join (T3 Left Join T4)
It's helpful to think of JOIN's in sequence, so the former is correct.
SELECT *
FROM a
INNER JOIN b ON b.a = a.id
INNER JOIN c ON c.b = b.id
LEFT JOIN d ON d.c = c.id
LEFT JOIN e ON e.d = d.id
Would be all the fields from a and b and c where all the ON criteria match, plus the values from d where its criteria match plus all the contents of e where all its criteria match.
I know RIGHT JOIN is perfectly acceptable, but I've found in my experience that it's unnecessary - I almost always just join things from left to right.
> Simple INNER JOIN VIEW code...
CREATE VIEW room_view
AS SELECT a.*,b.*
FROM j4_booking a INNER JOIN j4_scheduling b
on a.room_id = b.room_id;
You can apply join like this..
select a.*,b.*,c.*,d.*,e.*
from [DatabaseName].[Table_a] a
INNER JOIN [DatabaseName].[Table_b] b ON a.id = b.id
INNER JOIN [DatabaseName].[Table_c] c ON b.id=c.id
INNER JOIN [DatabaseName].[Table_d] d on c.id=d.id
INNER JOIN [DatabaseName].[Table_e] e on d.id=e.id where a.con=5 and
b.con=6
Here, at place of a.* and in where condition, you can show column(filed) which you like and according condition in where condition. You can insert more table and database as per your choice. But mind that you need to mention database name and alias if you work in different database.
Just tried the following from the Example DataBase given in W3School. Worked Fine for me.
SELECT Orders.OrderID, Customers.CustomerName, Orders.OrderDate, Products.ProductName, Products.ProductID
FROM Orders
INNER JOIN Products
INNER JOIN Customers
ON Orders.CustomerID=Customers.CustomerID;
Join used to combine rows from two or more tables, based on a related column between them. This example from Adventure works:
SELECT a.[EmailAddress],b.[FirstName],b.[LastName],c.[PhoneNumber],d.[Name]
FROM [Person].[EmailAddress] a
INNER JOIN [Person].[Person] b
ON a.BusinessEntityID = b.BusinessEntityID
INNER JOIN [Person].[PersonPhone] c
ON b.BusinessEntityID = c.BusinessEntityID
INNER JOIN [Person].[PhoneNumberType] d
ON c.phoneNumberTypeID = d.phoneNumberTypeID
SELECT * FROM Table A LEFT JOIN TABLE B LEFT JOIN TABLE C
From the snippet above, TABLE C will left join into (TABLE B) or (data from TABLE A LEFT JOIN TABLE B) or (TABLE A)?
TABLE C will left join into 1. (TABLE B) or 2. (data from TABLE A LEFT JOIN
TABLE B) or 3. (TABLE A)?
The second. But The join condition will help you to understand more.
You can write:
SELECT *
FROM Table A
LEFT JOIN TABLE B ON (A.id = B.id)
LEFT JOIN TABLE C ON (A.ID = C.ID)
But you are able to:
SELECT *
FROM Table A
LEFT JOIN TABLE B ON (A.id = B.id)
LEFT JOIN TABLE C ON (A.id = C.id and B.code = C.code)
So, you can join on every field from previous tables and you join on "the result" (though the engine may choose its way to get the result) of the previous joins.
Think at left join as non-commutative operation (A left join B is not the same as B left join A) So, the order is important and C will be left joined at the previous joined tables.
The Oracle documentation is quite specific about how the joins are processed:
To execute a join of three or more tables, Oracle first joins two of
the tables based on the join conditions comparing their columns and
then joins the result to another table based on join conditions
containing columns of the joined tables and the new table. Oracle
continues this process until all tables are joined into the result.
This is the logic approach to handling the joins and is consistent with the ANSI standard (in other words, all database engines process the joins in order).
However, when the query is actually executed, the optimizer may choose to run the joins in a different order. The result needs to be logically the same as processing the joins in the order given in the query.
Also, the join conditions may cause some unexpected conditions to arise. So if you have:
from A left outer join
B
on A.id = B.id left outer join
C
on B.id = C.id
Then, you might have the condition where A and C each have a row with a particular id, but B does not. With this formulation, you will not see the row in C because it is joining to NULL. So, be careful with join conditions on left outer join, particularly when joining to a table other than the first table in the chain.
You need to mentioned the column name properly in order to run the query. Let´s say if you are using:
SELECT *
FROM Table A
LEFT JOIN TABLE B ON (A.id = B.id)
LEFT JOIN TABLE C ON (A.id = C.id and B.code = C.code)
Then you may get the following error:
ORA-00933:SQL command not properly ended.
So to avoid it you can try:
SELECT A.id as "Id_from_A", B.code as "Code_from_B"
FROM Table A
LEFT JOIN TABLE B ON (A.id = B.id)
LEFT JOIN TABLE C ON (A.id = C.id and B.code = C.code)
Thanks
I have two tables, one has primary key other has it as a foreign key.
I want to pull data from the primary table, only if the secondary table does not have an entry containing it's key. Sort of an opposite of a simple inner join, which returns only rows that join together by that key.
SELECT <select_list>
FROM Table_A A
LEFT JOIN Table_B B
ON A.Key = B.Key
WHERE B.Key IS NULL
Full image of join
From aticle : http://www.codeproject.com/KB/database/Visual_SQL_Joins.aspx
SELECT
*
FROM
primarytable P
WHERE
NOT EXISTS (SELECT * FROM secondarytable S
WHERE
P.PKCol = S.FKCol)
Generally, (NOT) EXISTS is a better choice then (NOT) IN or (LEFT) JOIN
use a "not exists" left join:
SELECT p.*
FROM primary_table p LEFT JOIN second s ON p.ID = s.ID
WHERE s.ID IS NULL
Another solution is:
SELECT * FROM TABLE1 WHERE id NOT IN (SELECT id FROM TABLE2)
SELECT P.*
FROM primary_table P
LEFT JOIN secondary_table S on P.id = S.p_id
WHERE S.p_id IS NULL
If you want to select the columns from First Table "which are also present in Second table, then in this case you can also use EXCEPT. In this case, column names can be different as well but data type should be same.
Example:
select ID, FName
from FirstTable
EXCEPT
select ID, SName
from SecondTable
This was helpful to use in COGNOS because creating a SQL "Not in" statement in Cognos was allowed, but it took too long to run. I had manually coded table A to join to table B in in Cognos as A.key "not in" B.key, but the query was taking too long/not returning results after 5 minutes.
For anyone else that is looking for a "NOT IN" solution in Cognos, here is what I did. Create a Query that joins table A and B with a LEFT JOIN in Cognos by selecting link type: table A.Key has "0 to N" values in table B, then added a Filter (these correspond to Where Clauses) for: table B.Key is NULL.
Ran fast and like a charm.