I've got the following two tables (in MySQL):
Phone_book
+----+------+--------------+
| id | name | phone_number |
+----+------+--------------+
| 1 | John | 111111111111 |
+----+------+--------------+
| 2 | Jane | 222222222222 |
+----+------+--------------+
Call
+----+------+--------------+
| id | date | phone_number |
+----+------+--------------+
| 1 | 0945 | 111111111111 |
+----+------+--------------+
| 2 | 0950 | 222222222222 |
+----+------+--------------+
| 3 | 1045 | 333333333333 |
+----+------+--------------+
How do I find out which calls were made by people whose phone_number is not in the Phone_book? The desired output would be:
Call
+----+------+--------------+
| id | date | phone_number |
+----+------+--------------+
| 3 | 1045 | 333333333333 |
+----+------+--------------+
SELECT t1.ColumnID,
CASE
WHEN NOT EXISTS( SELECT t2.FieldText
FROM Table t2
WHERE t2.ColumnID = t1.ColumnID)
THEN t1.FieldText
ELSE t2.FieldText
END FieldText
FROM Table1 t1, Table2 t2
I think
SELECT CALL.* FROM CALL LEFT JOIN Phone_book ON
CALL.id = Phone_book.id WHERE Phone_book.name IS NULL
The code below would be a bit more efficient than the answers presented above when dealing with larger datasets.
SELECT * FROM Call WHERE
NOT EXISTS (SELECT 'x' FROM Phone_book where
Phone_book.phone_number = Call.phone_number)
Alternatively,
select id from call
minus
select id from phone_number
SELECT Call.ID, Call.date, Call.phone_number
FROM Call
LEFT OUTER JOIN Phone_Book
ON (Call.phone_number=Phone_book.phone_number)
WHERE Phone_book.phone_number IS NULL
Should remove the subquery, allowing the query optimiser to work its magic.
Also, avoid "SELECT *" because it can break your code if someone alters the underlying tables or views (and it's inefficient).
SELECT DISTINCT Call.id
FROM Call
LEFT OUTER JOIN Phone_book USING (id)
WHERE Phone_book.id IS NULL
This will return the extra id-s that are missing in your Phone_book table.
The code below would be a bit more efficient than the answers presented above when dealing with larger datasets.
SELECT * FROM Call WHERE
NOT EXISTS (SELECT 'x' FROM Phone_book where
Phone_book.phone_number = Call.phone_number)
SELECT DISTINCT Call.id
FROM Call
LEFT OUTER JOIN Phone_book USING (id)
WHERE Phone_book.id IS NULL
This will return the extra id-s that are missing in your Phone_book table.
SELECT Call.ID, Call.date, Call.phone_number
FROM Call
LEFT OUTER JOIN Phone_Book
ON (Call.phone_number=Phone_book.phone_number)
WHERE Phone_book.phone_number IS NULL
Should remove the subquery, allowing the query optimiser to work its magic.
Also, avoid "SELECT *" because it can break your code if someone alters the underlying tables or views (and it's inefficient).
SELECT name, phone_number FROM Call a
WHERE a.phone_number NOT IN (SELECT b.phone_number FROM Phone_book b)
I think
SELECT CALL.* FROM CALL LEFT JOIN Phone_book ON
CALL.id = Phone_book.id WHERE Phone_book.name IS NULL
SELECT Call.ID, Call.date, Call.phone_number
FROM Call
LEFT OUTER JOIN Phone_Book
ON (Call.phone_number=Phone_book.phone_number)
WHERE Phone_book.phone_number IS NULL
Should remove the subquery, allowing the query optimiser to work its magic.
Also, avoid "SELECT *" because it can break your code if someone alters the underlying tables or views (and it's inefficient).
SELECT t1.ColumnID,
CASE
WHEN NOT EXISTS( SELECT t2.FieldText
FROM Table t2
WHERE t2.ColumnID = t1.ColumnID)
THEN t1.FieldText
ELSE t2.FieldText
END FieldText
FROM Table1 t1, Table2 t2
Alternatively,
select id from call
minus
select id from phone_number
The code below would be a bit more efficient than the answers presented above when dealing with larger datasets.
SELECT * FROM Call WHERE
NOT EXISTS (SELECT 'x' FROM Phone_book where
Phone_book.phone_number = Call.phone_number)
SELECT name, phone_number FROM Call a
WHERE a.phone_number NOT IN (SELECT b.phone_number FROM Phone_book b)
SELECT Call.ID, Call.date, Call.phone_number
FROM Call
LEFT OUTER JOIN Phone_Book
ON (Call.phone_number=Phone_book.phone_number)
WHERE Phone_book.phone_number IS NULL
Should remove the subquery, allowing the query optimiser to work its magic.
Also, avoid "SELECT *" because it can break your code if someone alters the underlying tables or views (and it's inefficient).
Source: Stackoverflow.com