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
Related
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 ;
I have two tables -> tb1 and tb2.
I am performing left join operation on these tables using ID column and also i have one more condition such as one column is not equal to other column .
Below is sample code
select * from tb1 LEFT JOIN tb2 ON tb1.id=tb2.id AND tb1.pid!=tb2.pid;
I am able to get results from above query.
But i need to know is there any alternate ways to get same result using sql.?
The actually SQL standard uses <> instead of !=.
select * from tb1 LEFT JOIN tb2 ON tb1.id=tb2.id AND tb1.pid<>tb2.pid;
It seems to you not equal not working because of your join and join condition.
if we create two tables and create like your query
create table t1(id int,pid int);
create table t2 (id int,pid int );
insert into t1 values(1,2),(2,3),(3,4);
insert into t2 values(1,2),(2,3),(3,4);
select t1.* from t1 left join
t2 on t1.id=t2.id and
t1.pid!=t2.pid
order by t1.id
id pid
1 2
2 3
3 4
It returns all the values of 1st table, because LEFT JOIN returns all records from the left table (table1), and the matched records from the right table (table2). The result is NULL from the right side, if there is no match.
But if you put inner join in the same it will not return any row. so i think problem is not in the "not equal operator"
I have 3 tables of accounts that all contain the same fields. Table1 contains all accounts while Table2 and Table3 contain subsets of the accounts. I'm trying to select records in Table1 that do no exist in Table2 or Table3.
Let's say the table layout is like this and is the same for all 3 tables:
|AcctNum|Name|State|
I know how to do this if it was just Table1 and Table2, using a left join and Is Null, but the 3rd table is throwing me. Is this possible to do in one query? Can you combine left joins? I should point out I'm using Access 2010.
Yes you can combine left joins and with the odd syntax Access uses the query should look like this:
SELECT T1.AcctNum
FROM (Table1 AS T1 LEFT JOIN Table2 AS T2 ON T1.AcctNum = T2.AcctNum)
LEFT JOIN Table3 AS T3 ON T1.AcctNum = T3.AcctNum
WHERE (((T2.AcctNum) Is Null) AND ((T3.AcctNum) Is Null));
You can use Access to create a view called TableCombined that is a union of both Table2 and Table3.
At that point, you can use your left join and Is Null query and join TableCombined to Table1.
Hope this helps!
You can also do a NOT EXISTS statement which makes sense logically for what you are trying to achieve.
For example:
SELECT ACCTNUM
FROM TABLE1
WHERE NOT EXISTS (SELECT TABLE2.ACCTNUM FROM TABLE2 INNER JOIN TABLE3 WHERE TABLE2.ACCTNUM IS NULL AND TABLE3.ACCTNUM IS NULL)
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
How do i make one main table that has one instance of the column 'Instructor' and shows 'formsreturned' and 'availability_avg' next to the main 'Instructor' column?
Just create a standard INNER JOIN:
SELECT T1.Instructor, T1.Availability_Avg, T2.FormsReturned
FROM Table1 T1
INNER JOIN Table2 T2 ON T1.Instructor = T2.Instructor