MySQL Insert Where query

Question

What\'s wrong with this query:

INSERT INTO Users( weight, desiredWeight ) VALUES ( 160, 145 ) WHERE id = 1;

It works without the WHE

Answer 1

The right answer to this question will be sth like this:

a). IF want select before insert :

INSERT INTO Users( weight, desiredWeight ) 
  select val1 , val2  from tableXShoulatNotBeUsers
  WHERE somecondition;

b). IF record already exists use update instead of insert:

 INSERT INTO Users( weight, desiredWeight ) VALUES ( 160, 145 ) WHERE id = 1;

Should be

Update Users set weight=160, desiredWeight=145  WHERE id = 1;

c). If you want to update or insert at the same time

Replace Users set weight=160, desiredWeight=145  WHERE id = 1;

Note):- you should provide values to all fields else missed field in query 
        will be set to null

d). If you want to CLONE a record from SAME table, just remember you cann't select from table to which you are inserting therefore

 create temporary table xtable ( weight int(11), desiredWeight int(11) ;

 insert into xtable (weight, desiredWeight) 
    select weight, desiredWeight from Users where [condition]

 insert into Users (weight, desiredWeight) 
    select weight , desiredWeight from xtable;

I think this pretty covers most of the scenarios