I want to do the following:
I have a table called Name which has an ID field.
I have another blank table called Transcript
I want to take the ID#s from Name and insert them into Transcript where they do not exist.
Secondly I want to create 10 records with a different COURSE# value in the Transcript table.
Therefore for each Name.ID I would like 10 records in Transcript.ID with a different value under course # ie; 101,201,301
Something like this might work:
INSERT INTO TableB
SELECT TableA.id FROM TableA
LEFT OUTER JOIN TableB
ON TableA.name = TableB.name
WHERE TableB.id IS null
Another query that will return the same thing
INSERT INTO TABLEB
SELECT TableA.ID FROm TableA WHERE ID NOT IN (SELECT Id FROM TableB)
Assuming that you are getting your course numbers from some outside courses table, here is the t-sql:
INSERT INTO transcript (name_id, course_id)
SELECT n.name_id, c.course_id
FROM name n
CROSS APPLY courses c
WHERE n.last_name = 'xxx'
This will insert all of the courses in the table for all of the names found by the where clause.
Related
I face issue about duplicate data when join table, here my sample data table I have
-- Table A
I want to join with
-- Table B
this my query notation for join both table,
select a.trans_id, name
from tableA a
inner join tableB b
on a.ID_Trans = b.trans_id
and this the result, why I get the duplicating data which should show only two lines of data, please help me to solve this case.
Firstly, as you have been told multiple times in the comments, this is working exactly as you have written, and (more importantly) as intended. You have 2 rows in tableA and those 2 rows match 2 rows in your table tableB according to the ON clause. This means that each join operation, for the each of the rows in tableA, results in 2 rows as well; thus 4 rows (2 * 2 = 4).
Considering that your table, TableA only has one column then it seems that you should be cleaning up that data and deleting the duplicates. There are plenty of examples on how to do that already (example).
Perhaps the column you show us in TableA is one many, and thus instead you have a denormalisation issue, and instead there should be another table with the details of Id_trans and a PRIMARY KEY or UNIQUE CONSTRAINT/INDEX on it. Then you would join fron that table to TableB.
Finally, what you might be after is an EXISTS, which would look like this:
SELECT B.trans_id, B.[name]
FROM dbo.TableB B
WHERE EXISTS(SELECT 1
FROM dbo.TableA A
WHERE A.ID_Trans = B.trans_id); --Odd that it's called ID_Trans in one table, and Trans_ID in another
As the comments mentioned your query does exactly what you asked it to do but I think you wanted something like:
select a.trans_id, a.name, b.name
from tableA a
inner join tableB b on a.trans_id = b.trans_id
group by a.trans_id, a.name, b.name
Since there are two rows in both table with same ID join will make them four. You can use distinct to remove duplicates:
select distinct a.trans_id, name
from tableA a
inner join tableB b
on a.id_trans = b.trans_id
But I would suggest to use exists:
select trans_id, name
from tableB b
exists (select 1 from tableA a where a.trans_id=b.trans_id)
I have a Table A from where I have to copy Data to Table B. Now problem is In both table A and Table B there is a column ID which is primary key and can't be null.Table A is having Duplicates. Can any one tell me How to insert Data into Table B from Table A without Duplicates?
It would be something like
INSERT INTO TableA(ID) SELECT DISTINCT ID FROM TableB B LEFT JOIN TableA A ON A.ID = B.ID WHERE A.ID IS NULL
You can use the DISTINCT function in a select statement to remove duplicates.
In the example I'm going to assume that both tables have 3 columns called ID, Name and Surname:
insert into tableB (ID, Name, Surname)
select
distinct(ID) as ID
,Name
,Surname
from tableA
;
Please note that the DISTINCT function will provide distinct rows.
Here is my obstacle.
I have two tables. Table A contains more rows than Table B. I have to merge the results and if Table A does not contain a row from Table B then I insert it into the new set. If however, a row from Table A contains a row with the same primary key as Table B, the new set will take the row from Table B.
Would this best be done in a cursor or is there an easier way to do this? I ask because there are 20 million rows and while I am new to sql, i've heard cursors are expensive.
Your phrasing is a little vague. It seems that you want everything from TableB and then rows from TableA that have no matching primary key in B. The following query solves this problem:
select *
from tableB union all
select *
from tableA
where tableA.pk not in (select pk from tableB)
Yep, cursors are expensive.
There's a MERGE command in later versions of SQL that will do this in one shot, but it's sooo cumbersome. Better to do it in two pieces - first:
UPDATE A SET
field1 = B.field1
,field2 = B.field2
, etc
FROM A JOIN B on B.id = A.id
Then:
INSERT A SELECT * FROM B --enumerate fields if different
WHERE B.id not in (select id FROM A)
An OUTER JOIN should do what you need and be more efficient than a cursor.
Try this query
--first get the rows that match between TableA and TableB
INSERT INTO [new set]
SELECT TableB.* --or columns of your choice
FROM TableA LEFT JOIN TableB ON [matching key criteria]
WHERE TableB.[joining column/PK] IS NOT NULL
--then get the rows from TableA that don't have a match
INSERT INTO [new set]
SELECT TableA.* --you didn't say what was inserted if there was no matching row
FROM TableA LEFT JOIN TableB ON [matching key criteria]
WHERE TableB.[joining column/PK] IS NULL
I have data in 2 tables, and I want to create a report.
Table A:
tableAID (primary key)
name
Table B:
tableBID (primary key)
grade
tableAID (foreign key, references Table A)
There is much more to both tables, but those are the relevant columns.
The query I want to run, conceptually, is this:
select TableA.name, avg(TableB.grade) where TableB.tableAID = TableA.tableAID
The problem of course is that I'm using an aggregate function (avg), and I can rewrite it like this:
select avg(grade), tableAID from TableB group by tableAID
but then I only get the ID of TableA, whereas I really need that name column which appears in TableA, not just the ID.
Is it possible to write a query to do this in one statement, or would I first need to execute the second query I listed, get the list of id's, then query each record in TableA for the name column... seems to me I'm missing something obvious here, but I'm (quite obviously) not an sql guru...
You can do this:
SELECT avg(b.grade), a.tableAID, a.name
FROM TableA a
JOIN TableB b
ON b.tableAID = a.tableAID
GROUP BY a.tableAID, a.name
Just adding it to the group will work fine in your case.
SELECT AVG(TableB.grade), TableB.tableAID, TableA.Name
FROM TableA INNER JOIN TableB
ON TableA.TableAID = TableB.TableAID
GROUP BY TableA.tableAID, TableA.Name
Alternative answer:
SELECT AVG(b.grade), a.tableAID, MAX(a.name )
FROM TableA a
JOIN TableB b
ON b.tableAID = a.tableAID
GROUP BY a.tableAID
Just to get you thinking.
I have table A with close to 15000 entries. I have a second table B with 7900 entries with a common field with table A.
I need to extract into a third temporary tableC all entries from table A except the ones that also appear in table B. Simple as it may sound, i havent found a way to do it. The closest i got was this:
INSERT INTO tableC
SELECT *
FROM tableA
INNER JOIN tableB
ON tableA.field IS NOT tableB.field
This SQL just selects everything in tableA, even entries that are in tableB.
Any ideas where i'm going wrong?
What if you try this?
INSERT INTO tableC
SELECT *
FROM tableA
WHERE tableA.field NOT IN (SELECT tableB.field FROM tableB)
Or you can try the alternate EXISTS syntax
INSERT INTO tableC
SELECT *
FROM tableA
WHERE NOT EXISTS (SELECT * FROM tableB WHERE tableB.field = tableA.field)