I have multiple tables in my data set. I need two columns from one table to be pivoted against one column in a different table.
Code:
SELECT DISTINCT
table1.name,
table6.count,
table6.car_name
From Master_Table
Inner Join table1
On Master_Table.ID_SEQNO = table1.ID_SEQNO
Inner Join table2
On table1.table1_ID_SEQNO = table2.table1_ID_SEQNO
Inner Join table3
On table2.ID_SEQNO = table3.ID_SEQNO
Inner Join table4
On table3.ID_SEQNO = table4.ID_SEQNO
Left Outer Join table5
On table4.CANDIDATE_ID_SEQNO = table5.CANDIDATE_ID_SEQNO
Left Outer Join table6
On table5.ID_SEQNO = table6.ID_SEQNO
ORDER BY table1.name
Output I need:
What I have now :
Master_Table : Has names , Date, Time of ownership etc
table1 has info on each name , adress phone number email etc
table2 has info like cars insurance etc so on... I have used id_seqno to join statements without which the code doesn't work.
Each table has a id_seqno with which I map it to every other table... I am modifying an existing code so pretty new to this.
Related
I have 4 tables with one column is common on all tables. Is there a way to create a view where I can join all tables by same column where I see the common column only once.
Let's say I have table1
Cust ID | Order ID | Product_Name
Table2
Cust_ID | Cust_Name | Cust_Address
Table3
Cust_ID | Cust_Acc | Acc_Type
Table4
Cust_ID | Contact_Phone | Cust_Total_Ord
Here is the code I use to join tables;
SELECT *
FROM table1
LEFT JOIN table2 ON table1.Cust_ID = table2.Cust_ID
LEFT JOIN table3 ON table2.Cust_ID = table3.Cust_ID
LEFT JOIN table4 ON table3.Cust_ID = table4.Cust_ID
I get all tables joined by I see Cust_ID from each table as below;
Cust ID| Order ID|Product_Name| Cust_ID| Cust_Name|Cust_Address| Cust_ID| Cust_Acc| Acc_Type|Cust_ID|Contact_Phone|Cust_Total_Ord
Is there a way to remove duplicate Cust_ID columns or do I need to write each column name in the SELECT? I have more than 50 columns in total so will be difficult to write all.
Sorry if it is a really dumb question, I have checked previous similar questions but couldn't figure out and thanks for help.
you have common columns on all tables so could use using(common_column) to remove duplicated columns.
SELECT *
FROM table1
LEFT JOIN table2 using(Cust_ID)
LEFT JOIN table3 using(Cust_ID)
LEFT JOIN table4 using(Cust_ID)
I hop that useful.
you need to select columns from three tables first and then make inner join like below
select
t1.cust_id, t1.col1, t1.col2,
t2.col1_table2, t2.col2_table2,
t3.col1_table3, t3.col2_table3
from
table1 t1
inner join
table2 t2 on t1.cust_id = t2.cust_id
join table3 t3 on t1.cust_id = t3.cust_id
Result as shown in below image
No, you cannot easily do what you want in SQL Server. In other databases, you can use the using clause.
One thing you can do is select the columns explicitly from all but the first table:
SELECT t1.*, . . .
FROM table1 t1 LEFT JOIN
table2 t2
ON t1.Cust_ID = t2.Cust_ID LEFT JOIN
table3
ON t1.Cust_ID = table3.Cust_ID LEFT JOIN
table4
ON t1.Cust_ID = table4.Cust_ID;
Perhaps more important than the column issue, I changed the join conditions. You are using LEFT JOIN, so the first table is the "driving" table. When you say t2.Cust_ID = t3.Cust_Id, this returns true only when there was a match to table2. In general, you want to use the columns from table1, because it is the first one in the chain of LEFT JOINs.
How can I join three or four SQL tables that DO NOT have an equal amount of rows while ensuring that there are no duplicates of a primary/foreign key?
Structure:
Table1: id, first_name, last_name, email
Table2: id (independent of id in table 1), name, location, table1_id, table2_id
Table3: id, name, location
I want all of the data from table 1, then all of the data from table 2 corresponding with the table1_id without duplicates.
Kind of tricky for a new guy...
Not sure what do you want to do with Table3.
A LEFT JOIN returns all records from the LEFT table, and the matched records from the right table. If there is no match (from the right side), then the result is NULL.
So per example:
SELECT * FROM Table1 AS t
LEFT JOIN Table2 AS tt
ON t.id = tt.id
The LEFT table refers to the table statement before the LEFT JOIN, and the RIGHT table refers to the table statement after the LEFT JOIN. If you want to add in Table3 as well, use the same logic:
SELECT * FROM Table1 AS t
LEFT JOIN Table2 AS tt
ON t.id = tt.id
LEFT JOIN Table3 AS ttt
ON t.id = ttt.id
Note, that I use alias names for the tables (by using AS), so that I can more easily refer to a specific table. For example, t refers to Table1, tt refers to Table2, and ttt refers to Table3.
Joins are often used in SQL, therefore it is useful to look into: INNER JOIN, RIGHT JOIN, FULL JOIN, and SELF JOIN, as well.
Hope this helps.
Good luck with learning!
You will want to use an LEFT JOIN
SELECT * FROM table1 LEFT JOIN table2 ON Table1.ID = Table2.table1_id
I'm doing an assignment for class, and I'm at my whits end. Basically, I need to write a query that uses INNER JOIN's to combine all the data in 4 tables, while avoiding having titles columns with identical names (Ie Table1.Master_Number and Table2.Master_Number). The literal instructions are as follows:
Step 1: Create a view of all the columns (only list the columns once if the columns are duplicated in the tables) in all the tables of the Lecture 5 database. Save this query as Lecture_5_View and us this query to build the following 3 queries. In the “FROM” clause, you MUST use an “INNER JOIN” in this query. Remember ACCESS does not support the “CREATE VIEW” command so you must create a select query. `
Here is a screenshot of the database, that shows all the headings and column headings.
Based on other posts like this, I thought that it would be pretty simple. I have this so far, but it does not want to run
(ie Syntax error(missing operator) in query expression 'Table1.Master_Number = Table2.Master_Number INNER JOIN Table4 ON Table1.Master_Number = Table4.Master_Number)
SELECT *
FROM Table1
INNER JOIN Table2 ON Table1.Master_Number = Table2.Master_Number
INNER JOIN Table4 ON Table1.Master_Number = Table4.Master_Number
Where am I going wrong so far and how to I accomplish this query?
Much thanks,
Josh
With Access you need to use parentheses when doing more than one join:
SELECT *
FROM (Table1
INNER JOIN Table2
ON Table1.Master_Number = Table2.Master_Number)
INNER JOIN Table4
ON Table1.Master_Number = Table4.Master_Number;
This is essentiall spliting down you query so you have at most one join per section, i.e. Your First query is:
SELECT *
FROM Table1
INNER JOIN Table2
ON Table1.Master_Number = Table2.Master_Number;
Then you have:
SELECT *
FROM YourFirstQuery
INNER JOIN Table4
ON Table1.Master_Number = Table4.Master_Number;
This differs slightly from subqueries as you are still able to reference all fields from Table1 and Table2.
EDIT
To avoid duplicating columns you will need to explicitly list the columns you want (although you should be doing this anyway):
SELECT Table1.Master_Number,
Table1.Asset_Tag,
Table1.Serial_Number,
Table2.Last_Name,
Table2.First_Name,
Table4.Office_Number,
Table4.Location,
Table4.Department
FROM (Table1
INNER JOIN Table2
ON Table1.Master_Number = Table2.Master_Number)
INNER JOIN Table4
ON Table1.Master_Number = Table4.Master_Number;
Try this:
SELECT * FROM ((Table1
INNER JOIN Table2
ON Table1.Master_Number = Table2.Master_Number)
INNER JOIN Table4
ON Table1.Master_Number = Table4.Master_Number)
I have several tables that I am joining that I need to add another table to and I can't seem to get the right query. Here is what I have now -
Table 1
carid, catid, makeid, modelid, caryear
Table 2
makeid, makename
Table 3
modelid, modelname
Table 4
catid, catname
The query I am using to join these is:
SELECT * FROM table1 a
JOIN table2 b on a.makeid=b.makeid
JOIN table3 c on a.modelid=c.modelid
JOIN table4 d on a.catid=d.catid
WHERE a.carid = $carid;
Now I need to add a 5th table that I am getting from a 3rd party that I am having a hard time adding to my existing query. The new table has these fields -
Table 5
id, year, make, model, citympg, hwympg
I need the citympg and hwympg based on caryear from table 1, makename from table 2, and modelname from table 3. I know I can do a second query with those values, but I would prefer to do a single query and have all of the data in a single row. Can this be done in a single query? If so, how?
it's possible to have more than condition in a join.
does this work?
SELECT a.*, e.citympg, e.hwympg
FROM table1 a
JOIN table2 b on a.makeid=b.makeid
JOIN table3 c on a.modelid=c.modelid
JOIN table4 d on a.catid=d.catid
Join table5 e on b.makename = e.make
and c.modelname = e.model
and a.caryear = e.year
WHERE a.carid = $carid;
...though your question is not clear. Did you only want to join table5 to the others, or was there something else you wanted to do with table5?
Without indexes, It won't be efficient, but you can do
LEFT JOIN table5 ON (table2.make = table5.make AND table3.model = table5.model AND table1.caryear = table5.caryear)
This also assumes the make and models and years strings match exactly.
For example, there are two tables:
create table Table1 (id int, Name varchar (10))
create table Table2 (id int, Name varchar (10))
Table1 data as follows:
Id Name
-------------
1 A
2 B
Table2 data as follows:
Id Name
-------------
1 A
2 B
3 C
If I execute both below mentioned SQL statements, both outputs will be the same:
select *
from Table1
left join Table2 on Table1.id = Table2.id
select *
from Table2
right join Table1 on Table1.id = Table2.id
Please explain the difference between left and right join in the above SQL statements.
Select * from Table1 left join Table2 ...
and
Select * from Table2 right join Table1 ...
are indeed completely interchangeable. Try however Table2 left join Table1 (or its identical pair, Table1 right join Table2) to see a difference. This query should give you more rows, since Table2 contains a row with an id which is not present in Table1.
Table from which you are taking data is 'LEFT'.
Table you are joining is 'RIGHT'.
LEFT JOIN: Take all items from left table AND (only) matching items from right table.
RIGHT JOIN: Take all items from right table AND (only) matching items from left table.
So:
Select * from Table1 left join Table2 on Table1.id = Table2.id
gives:
Id Name
-------------
1 A
2 B
but:
Select * from Table1 right join Table2 on Table1.id = Table2.id
gives:
Id Name
-------------
1 A
2 B
3 C
you were right joining table with less rows on table with more rows
AND
again, left joining table with less rows on table with more rows
Try:
If Table1.Rows.Count > Table2.Rows.Count Then
' Left Join
Else
' Right Join
End If
You seem to be asking, "If I can rewrite a RIGHT OUTER JOIN using LEFT OUTER JOIN syntax then why have a RIGHT OUTER JOIN syntax at all?" I think the answer to this question is, because the designers of the language didn't want to place such a restriction on users (and I think they would have been criticized if they did), which would force users to change the order of tables in the FROM clause in some circumstances when merely changing the join type.
select fields
from tableA --left
left join tableB --right
on tableA.key = tableB.key
The table in the from in this example tableA, is on the left side of relation.
tableA <- tableB
[left]------[right]
So if you want to take all rows from the left table (tableA), even if there are no matches in the right table (tableB), you'll use the "left join".
And if you want to take all rows from the right table (tableB), even if there are no matches in the left table (tableA), you will use the right join.
Thus, the following query is equivalent to that used above.
select fields
from tableB
right join tableA on tableB.key = tableA.key
Your two statements are equivalent.
Most people only use LEFT JOIN since it seems more intuitive, and it's universal syntax - I don't think all RDBMS support RIGHT JOIN.
I feel we may require AND condition in where clause of last figure of Outer Excluding JOIN so that we get the desired result of A Union B Minus A Interaction B.
I feel query needs to be updated to
SELECT <select_list>
FROM Table_A A
FULL OUTER JOIN Table_B B
ON A.Key = B.Key
WHERE A.Key IS NULL AND B.Key IS NULL
If we use OR , then we will get all the results of A Union B
select *
from Table1
left join Table2 on Table1.id = Table2.id
In the first query Left join compares left-sided table table1 to right-sided table table2.
In Which all the properties of table1 will be shown, whereas in table2 only those properties will be shown in which condition get true.
select *
from Table2
right join Table1 on Table1.id = Table2.id
In the first query Right join compares right-sided table table1 to left-sided table table2.
In Which all the properties of table1 will be shown, whereas in table2 only those properties will be shown in which condition get true.
Both queries will give the same result because the order of table declaration in query are different like you are declaring table1 and table2 in left and right respectively in first left join query, and also declaring table1 and table2 in right and left respectively in second right join query.
This is the reason why you are getting the same result in both queries. So if you want different result then execute this two queries respectively,
select *
from Table1
left join Table2 on Table1.id = Table2.id
select *
from Table1
right join Table2 on Table1.id = Table2.id
Select * from Table1 t1 Left Join Table2 t2 on t1.id=t2.id
By definition: Left Join selects all columns mentioned with the "select" keyword from Table 1 and the columns from Table 2 which matches the criteria after the "on" keyword.
Similarly,By definition: Right Join selects all columns mentioned with the "select" keyword from Table 2 and the columns from Table 1 which matches the criteria after the "on" keyword.
Referring to your question, id's in both the tables are compared with all the columns needed to be thrown in the output. So, ids 1 and 2 are common in the both the tables and as a result in the result you will have four columns with id and name columns from first and second tables in order.
*select *
from Table1
left join Table2 on Table1.id = Table2.id
The above expression,it takes all the records (rows) from table 1 and columns, with matching id's from table 1 and table 2, from table 2.
select *
from Table2
right join Table1 on Table1.id = Table2.id**
Similarly from the above expression,it takes all the records (rows) from table 1 and columns, with matching id's from table 1 and table 2, from table 2. (remember, this is a right join so all the columns from table2 and not from table1 will be considered).