What\'s wrong with this query:
INSERT INTO Users( weight, desiredWeight ) VALUES ( 160, 145 ) WHERE id = 1;
It works without the WHE
It doesn't make sense... even literally
INSERT means add a new row and when you say WHERE you define which row are you talking about in the SQL.
So adding a new row is not possible with a condition on an existing row.
You have to choose from the following:
A. Use UPDATE instead of INSERT
B. Use INSERT and remove WHERE clause ( I am just saying it...) or if you are real bound to use INSERT and WHERE in a single statement it can be done only via INSERT..SELECT clause...
INSERT INTO Users( weight, desiredWeight )
SELECT FROM Users WHERE id = 1;
But this serves an entirely different purpose and if you have defined id as Primary Key this insert will be failure, otherwise a new row will be inserted with id = 1.