When I use update to modify the data in mysql:
update table set col1=A,col2=B,col3=C where col4=D;
If A and B are the same, and C is not, will mysql write these 3 cols to the disk?
When I use update to modify the data in mysql:
update table set col1=A,col2=B,col3=C where col4=D;
If A and B are the same, and C is not, will mysql write these 3 cols to the disk?