Is there a way of doing something like a vlookup in presto?
I am given a bunch of IDs in one table that looks like this.
I have another table that gives me back the lookup values. so 503203 would have a particular name, a price, and a category.
How can I add three columns after each named product to show me the corresponding values? some thing like this?
Use left join:
select t1.*,
t21.*, t22.*, t23.*, t24.*
from table1 t1 left join
table1 t21
on t1.product1 = t21.productid left join
table1 t22
on t1.product2 = t22.productid left join
table1 t23
on t1.product1 = t23.productid left join
table1 t24
on t1.product1 = t24.productid ;
Related
I need find the most efficient way to join one table, to other three, using as criteria the values on theirs [Id_Orig] fields
Consider Table1 as the one with our universe of data, having the fields Below:
Select Id_Orig, F1, F2 From Table1
The field [Id_Orig] can have only three values: 'DO', 'CC' and 'DP'. I need to join other three tables with Table1, based on those values as shown below:
Table1 left join Table_DO : only for those records that have both [Id_Orig] = 'DO'
Table1 left join Table_CC : only for those records that have both [Id_Orig] = 'CC'
Table1 left join Table_DP : only for those records that have both [Id_Orig] = 'DP'
Suppose that Table1 has 1000 records, these must remain unchanged. The idea is only to add the fields from the other respective linked tables, as shown below:
Table1.Id_Orig, Table1.F1, Table1.F2, Table_DO.*, Table_CC.*, Table_DP.*
Can anyone tell me, please, how is the best way to achieve that, and if that could be done on the 'ON' Clause after the Left Join?
Thanks in advance.
Leopoldo Fernandes
Portugal
Try something like:
SELECT t1.*, tdo.*, tcc.*, tdp*
FROM Table1 AS t1
LEFT OUTER JOIN Table_DO AS tdo ON t1.[Id_Orig] = tdo.[Id_Orig] AND t1.[Id_Orig] = 'DO'
LEFT OUTER JOIN Table_CC AS tcc ON t1.[Id_Orig] = tcc.[Id_Orig] AND t1.[Id_Orig] = 'CC'
LEFT OUTER JOIN Table_DP AS tdp ON t1.[Id_Orig] = tdp.[Id_Orig] AND t1.[Id_Orig] = 'DP'
For example, when you JOIN to Table_DO, you said you want when both tables have [Id_Orig] = 'DO' ... since the JOIN condition is the values are equal, you only need to specify one column (I choose Table1).
Best way is to explain in pseudo code
How do I Get x,
When table1.activity == "some_string"
Then x = table1.line_number in that same row.
I'm doing an INNER JOIN and I'm doing checks on table 2. Basically I don't want to join that row if table1.activity == "some_string"
well it's not mentioned table2 in your pseudo code
but you could filter values in the inner join ON statement or WHERE statement of the query. It depends what you want By example, (In where Section)
SELECT * FROM table1 AS pivot
INNER JOIN table2 USING(id)
WHERE pivot.activity <>'not_want_these_kind_of_Records';
Or in ON Section
SELECT * FROM table1 AS pivot
INNER JOIN table2 AS t2 ON t2.id=pivot.id
AND t2.activity <>'not_want_these_kind_of_Records';
The second One filter the results before join to the pivot table
Regards
I have one table that contains lots of data and I want to select everything from this one.
Another table contains different statuscodes ( fields ID and text ), and I want to join this table into the first one so i get something like
All data from first table id1,text2,id2,text2 or id1,id2,text1,text2 from the second table.
USe LEFT OUTER JOIN
Select T1.*,T2.ID,T2.Text
from firstTable t1
LEFT OUTER JOIN SecondTable T2
on T1.<col>=T2.<col>
You can use join like this whether it may be left/right/inner join
SELECT t1.*,t2.id,t2.text
FROM table1 t1
LEFT JOIN table2 t2
ON t2.column_name=t1.column_name
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).
I am a little confused as to how to approach this SQL query.
I have two tables (equal number of records), and I would like to return a column with which is the division between the two.
In other words, here is my not-working-correctly query:
SELECT( (SELECT v FROM Table1) / (SELECT DotProduct FROM Table2) );
How would I do this? All I want it a column where each row equals the same row in Table1 divided by the same row in Table2. The resulting table should have the same number of rows, but I am getting something with a lot more rows than the original two tables.
I am at a complete loss. Any advice?
It sounds like you have some kind of key between the two tables. You need an Inner Join:
select t1.v / t2.DotProduct
from Table1 as t1
inner join Table2 as t2
on t1.ForeignKey = t2.PrimaryKey
Should work. Just make sure you watch out for division by zero errors.
You didn't specify the full table structure so I will assume a common ID column to link rows in the tables.
SELECT table1.v/table2.DotProduct
FROM Table1 INNER JOIN Table2
ON (Table1.ID=Table2.ID)
You need to do a JOIN on the tables and divide the columns you want.
SELECT (Table1.v / Table2.DotProduct) FROM Table1 JOIN Table2 ON something
You need to substitue something to tell SQL how to match up the rows:
Something like: Table1.id = Table2.id
In case your fileds are both integers you need to do this to avoid integer math:
select t1.v / (t2.DotProduct*1.00)
from Table1 as t1
inner join Table2 as t2
on t1.ForeignKey = t2.PrimaryKey
If you have multiple values in table2 relating to values in table1 you need to specify which to use -here I chose the largest one.
select t1.v / (max(t2.DotProduct)*1.00)
from Table1 as t1
inner join Table2 as t2
on t1.ForeignKey = t2.PrimaryKey
Group By t1.v