Home >> FAQs/Tutorials >> MySQL Tutorials

MySQL Tutorial - Error: Subquery Returns More than 1 Row

By: FYIcenter.com

(Continued from previous topic...)

What Happens If the UPDATE Subquery Returns Multiple Rows?

If a subquery is used in a UPDATE statement, it must return exactly one row for each row in the update table that matches the WHERE clause. If it returns multiple rows, MySQL server will give you an error message. To test this out, you can try the following tutorial exercise:

mysql> INSERT INTO fyi_rates VALUES (0, 'Number 1');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO fyi_rates VALUES (0, 'Number 2');
Query OK, 1 row affected (0.00 sec)

mysql> SELECT * FROM fyi_rates WHERE id = 0;
+------+----------+
| id   | comment  |
+------+----------+
|    0 | Number 1 |
|    0 | Number 2 |
+------+----------+
2 rows in set (0.00 sec)

mysql> UPDATE fyi_links SET notes = (
    SELECT comment FROM fyi_rates 
    WHERE fyi_rates.id = fyi_links.id
   ) 
   WHERE id = 0;
ERROR 1242 (21000): Subquery returns more than 1 row

(Continued on next topic...)

  1. What Are DML Statements?
  2. How To Create a Testing Table?
  3. How To Insert a New Row into a Table?
  4. How To Specify Default Values in INSERT Statement?
  5. How To Omit Columns with Default Values in INSERT Statement?
  6. What Happens If Unique Value Constraints Are Violated?
  7. How To Insert Multiple Rows with One INSERT Statement?
  8. How To Update Values in a Table?
  9. How To Update Column Values on Multiple Rows?
  10. How To Use Existing Column Values in the SET Clause?
  11. Is the Order of Columns in the SET Clause Important?
  12. How To Use Values from Other Tables in UPDATE Statements?
  13. What Happens If the UPDATE Subquery Returns No Rows?
  14. What Happens If the UPDATE Subquery Returns Multiple Rows?
  15. How To Delete an Existing Row from a Table?
  16. How To Delete Multiple Rows from a Table?
  17. How To Delete All Rows in a Table?

MySQL Tutorials:

More...


Other Tutorials/FAQs:

More...


Related Resources:

More...


Selected Jobs:

More...