I would appreciate if someone could help out.
There are two tables that I need to combine. So far I have been doing this every time.
SELECT * INTO TABLE_3
FROM TABLE_1 LEFT JOIN TABLE_2
ON TABLE_1.[DATE] = TABLE_2.[DATE1]
However, I would like to skip the part of creating a new table and insert the columns I need directly into the existing table.
I tried doing this,
INSERT INTO [TABLE_1] (USD,EUR,RUR)
SELECT USD,EUR,RUR
FROM TABLE_1 AS T1 LEFT JOIN TABLE_2 AS T2
ON T1.[DATE] = T2.[DATE1]
but got an error saying that my column names are ambiguous
I use SQL server 2014.
Instead of giving the column name directly, please specify the alias name to say from which table the column should take. May be here both tables having same column the you are trying to select. You should specify the exact table
INSERT INTO [TABLE_1] (USD,EUR,RUR)
SELECT [T1/T2].USD,[T1/T2].EUR,[T1/T2].RUR
FROM TABLE_1 AS T1 LEFT JOIN TABLE_2 AS T2
ON T1.[DATE] = T2.[DATE1]
Either you can specify T1 or T2 as per your business logic. Please rewrite the query as mentioned here. This will solve the problem. Please try this.
Related
I have a table A which loaded from a external stage, one column col1 has special char for example 'Español'. I need to join tableA with tableB
select * from tableA
join tableB
on tableA.col1 = tableB.col1
I know tableB.col1 has exactly same value 'Español', but this join couldn't catch it. Anyone knows why and how to get it joined?
Thanks.
If the join is failing it is because the values in col1 are not equivalent even though they might look the same when displayed. I wonder if using hex_encode(col1) on each table might surface the difference?
We have a query that looks for discrepancies between two tables in two different databases (one SQL Server, one Oracle) that in theory should always be in sync. The query pulls the data from both tables into table variables and then does a FULL OUTER JOIN to find the discrepancies. We suspect that the FULL OUT JOIN is partially to blame for the performance issues.
Would it make sense to rely on two LEFT OUTER JOINs and look for records that don't exist on the right side of the join?
We're also thinking about using temp tables to further help with performance.
One option is to do a inner join and store results in a temp table. Then do a select from TableA where not exists in tempTableWithCommonRecords
and another select from TableB where not exists in tempTableWithCommonRecords
Cant say if this will perform better as don't have enough info for that. Its just another option.
You can try the EXCEPT operator which handles complex joins, and it should work in both PL-SQL and T-SQL. It will return any values in the left table that are not a perfect match on the right table:
SELECT [Field1], [Field2], [Field3]
FROM Table1
EXCEPT
SELECT [Field1], [Field2], [Field3]
FROM Table2
UNION
SELECT [Field1], [Field2], [Field3]
FROM Table2
EXCEPT
SELECT [Field1], [Field2], [Field3]
FROM Table1
Stupidly simple question, but I just don't know what to google!
If I create a query like this:
Select id, data
from table1
Now I want to join with table2. I can immediately see that the id column is no longer unique and I have to change it to
table1.id
Is there any smart way (like a keyboard-shortcut) to do this, instead of manually adding table1 to every column? Either before I add the Join to secure that all columns will be unique, or after with suggestions based on the different possible tables.
No, there is no helper.
But do not you can alias the table name:
select x.Col1, y.Col2
from ALongTableName x
inner join AReallyReallyLongTableName y on x.Id = y.OtherId
which can also make queries clearer, and is very much necessary when doing self joins.
First of all, you should start using aliases:
SQL aliases are used to give a database table, or a column in a table,
a temporary name.
Basically aliases are created to make column names more readable.
This will narrow down your problem and make your code maintenance easier. If that's not enough, I guess you could start using auto-completion tools, such as these:
SQL Complete
SQL Prompt
ApexSQL Complete
These have your desired functionality, however, they do not always work as expected (at least for me).
Oh! You can use alias table name. Like this:
SELECT A.ID, A.data
FROM TableA A
INNER JOIN TableB B
ON A.ID = B.ID
You just only use A. or B. if two table have same this column selected. If they different, you don't need: Like this:
SELECT A.ID, data -- if Table B not have column data
FROM TableA A
INNER JOIN TableB B
ON A.ID = B.ID
Or:
Select A.*, B.ID
FROM TableA A
INNER JOIN TableB B
ON A.ID = B.ID
I have a couple of tables that have data in them that I am looking to get information from. Here is the rundown....In table 1 I have bunch of columns that I am pulling data from, one of the columns is a user ID (which is a number)that was the last userID to modify a record. In table 2 I want to pull in the name of that user based on the ID that is pulled from the other table (this table has both the userID and the username).
so my final query would have the columns in table 1 as well as the username from table 2 to show that was the user to last edit the record. I assume this has to be done in a nested select statement but for the life of me I cannot come up with the correct syntax.
Can anyone help me out?
Thanks
Jeff
Yes, you need a very basic join that link both tables together.
Select t1.UserID,
t2.UserName
FROM table1 t1 INNER JOIN
table2 t2 ON t1.userid=t2.userid
select t1.*, t2.{username} from table1 as t1
join table2 as t2 on t1.{userId}=t2.{userid};
change {username} with the actual column name of user
similarly {userId} with appropriate column name in tables.
Hope it helps you.
this is standard inner join query, to learn more consider reading: http://www.w3schools.com/sql/
I'm trying to update some rows in a table joined to another table. The left table is indexed by ID; the right table is joined on the same ID but has multiple rows per ID. My query looks like:
UPDATE t1
SET t1.modified = t2.created
FROM table1 t1
INNER JOIN table2 t2
ON t1.ID = t2.ID
Note that t1.modified and t2.created are both datetime.
As stated, t2 has several rows per ID, each with a different created value (so the primary key is t2, created). What I want to do is set the max value of t2.created=t1.modified. However, when joining, the t1.modified value gets updated in no particular order, so whichever row is updated last, that's the value that t1.modified gets. I tried using t1.modified=max(t2.created), but apparently I can't use aggregate functions in an update query, nor can I use an order clause (i.e. order the rows so that the last row updated will effectively be the latest value of t2.created) in the update query.
Any help you can provide me is much appreciated! Thanks!!
how about this? will this fit your need?
UPDATE t1
SET modified = isnull((SELECT max(t2.created)
FROM table2 t2
WHERE t2.ID = t1.ID), modified)
FROM table1 t1;
Use the isnull function to set modified to be itself if the value returned is null. that should take care of the null issue.
You could do it this way, although it may not be standard SQL. However it should work for SQL Server.
update t1
set t1.modified = (select max([created]) from t2 where t1.ID = t2.id)