SQL DELETE From with sub query syntax error - sql

Question

I am having difficulty runing SQL code in MS Access 2010. I would like to ask for help in reviewing and correcting it.
Data:
- two tables with names: Tbl_001_WholeBase and Tbl_002_NewKVG
- they have connected by column named Key
Problem:
I want to delete all rows from Tbl_001_WholeBase which have Key that is not available in table Tbl_002_NewKVG
Example:
Tbl_001_WholeBase
ID Key
1 Hronic1
2 Hronic2
3 Hronic3
Tbl_002_NewKVG
ID Key
1 Hronic1
2 Hronic2
So as a result I would like to leave in Tbl_001_WholeBase only 3rd record, base would look like this:
ID Key
3 Hronic3
What I wanted to use in Access was:
DELETE
FROM Tbl_001_WholeBase
WHERE Tbl_001_WholeBase.KEY IN
(SELECT *
FROM Tbl_001_WholeBase
LEFT JOIN Tbl_002_NewKVG
ON Tbl_001_WholeBase.Key = Tbl_002_NewKVG.Key
WHERE (((Tbl_002_NewKVG.Key) Is Null)));
The subquery is working properly, however I can't connect it with Delete statement.
Error I got when running this code is:
You have written a subquery that can return more than one field without using the Exists reserved word in the main query's FROM clause. Revise the SELECT statement of the subquery to request only one field.

Answer 1

Select a key in subquery instead of (*)
DELETE
FROM Tbl_001_WholeBase
WHERE Tbl_001_WholeBase.KEY IN
(SELECT keyId
FROM Tbl_001_WholeBase
LEFT JOIN Tbl_002_NewKVG
ON Tbl_001_WholeBase.Key = Tbl_002_NewKVG.Key
WHERE (((Tbl_002_NewKVG.Key) Is Null)));
Here keyId will be your column name or your unique key through which you want to delete the row.

Answer 2

Join the two tables using a LEFT JOIN.
This will return all records from the table on the left of the join, and any matching records from the table on the right. NULL is used where the record on the right isn't available.
SELECT *
FROM Tbl_001_WholeBase LEFT JOIN Tbl_001_NewKVG ON Tbl_001_WholeBase.Key = Tbl_001_NewKVG.Key
| Tbl_001_WholeBase.ID | Tbl_001_WholeBase.Key | Tbl_001_NewKVG.ID | Tbl_001_NewKVG.Key |
|----------------------|-----------------------|-------------------|--------------------|
| 1 | Hronic1 | 1 | Hronic1 |
| 2 | Hronic2 | 2 | Hronic2 |
| 3 | Hronic3 | NULL | NULL |
You can see that the last NewKVG.Key is NULL, so you can omit it from the results:
SELECT *
FROM Tbl_001_WholeBase LEFT JOIN Tbl_001_NewKVG ON Tbl_001_WholeBase.Key = Tbl_001_NewKVG.Key
WHERE NOT Tbl_001_NewKVG.Key IS NULL
| Tbl_001_WholeBase.ID | Tbl_001_WholeBase.Key | Tbl_001_NewKVG.ID | Tbl_001_NewKVG.Key |
|----------------------|-----------------------|-------------------|--------------------|
| 1 | Hronic1 | 1 | Hronic1 |
| 2 | Hronic2 | 2 | Hronic2 |
Or you can delete it from the table:
DELETE DISTINCTROW Tbl_001_WholeBase.*
FROM Tbl_001_WholeBase LEFT JOIN Tbl_001_NewKVG ON Tbl_001_WholeBase.Key = Tbl_001_NewKVG.Key
WHERE NOT Tbl_001_NewKVG.Key IS NULL
| ID | Key |
|----------|----------|
| #Deleted | #Deleted |
| #Deleted | #Deleted |
| 3 | Hronic3 |

Answer 3

Use EXISTS:
DELETE FROM Tbl_001_WholeBase
WHERE EXISTS (SELECT 1
FROM Tbl_002_NewKVG
WHERE Tbl_001_WholeBase.Key = Tbl_002_NewKVG.Key
);
Or use IN with no JOIN:
DELETE FROM Tbl_001_WholeBase
WHERE Tbl_001_WholeBase.Key IN (SELECT Tbl_002_NewKVG.Key
FROM Tbl_002_NewKVG
);