php - On Duplicate Key Update - Multiple Columns

Question

When using insert... on duplicate key update, what is the syntax to update multiple columns?

INSERT INTO table1 (col1, col2, col3, col4) VALUES (’$val1’, ‘$val2’, ‘$val3’, ‘$val4’)
ON DUPLICATE KEY UPDATE col2=‘$val2’, col3=‘$val3’, col4=‘$val4’ // <-- not sure

Update: I am using this within PHP. Since this is a syntax question, it very relevant.

$result = mysql_query("INSERT INTO table1 (col1, col2, col3, col4) 
                         VALUES (’$val1’, ‘$val2’, ‘$val3’, ‘$val4’)
                         ON DUPLICATE KEY UPDATE (col2=‘$val2’, col3=‘$val3’, col4=‘$val4’)")

Again, not sure about this last part with the "Update".

Answer 1

Well, this is old. But of course you only need to provide a value once, there's no reason to add it a second time in the query (which comes in handy for multiple inserts, or prepared statements):

INSERT INTO table1
  (col1, col2, col3, col4)
VALUES
  ('val1', 'val2', 'val3', 'val4')
ON DUPLICATE KEY UPDATE
  col2=VALUES(col2),
  col3=VALUES(col3) [,...]

Which has as advantage it will still work for a multiple insert statement:

INSERT INTO table1
  (col1, col2, col3, col4)
VALUES
  ('val1', 'val2', 'val3', 'val4'),
  ('val5', 'val6', 'val7', 'val8'),
  ('val9', 'val10', 'val11', 'val12')
ON DUPLICATE KEY UPDATE
  col2=VALUES(col2),
  col3=VALUES(col3) [,...]