The simple SQL query to accomplish this is:
update t1
set t1.c1=t2.c1,
t1.c2=t2.c2
from table1 t1
inner join table2 t2
on t1.col=t2.col
In this script example, we are updating table 1 (t1) by setting a column (t1.c1) to the value of the column of table 2's column (t2.c1) - the next line shows another column being updated with the same table two, but using a different column.
Next, we are telling it to take this information from table 1 t1 - the t1 is the alias of table 1. Then we join table 2 (t2) into the query with the INNER JOIN statement. The join basically says that table2 is using alias "t2" and that we want column 1 in table 1 to equal column 1 in table 2 for our equality condition to be met. So, if column 1 in table 1 is apples and column 1 in table 2 is apples and the column we are updating is "price", then we would see something like this:
update t1
set t1.price = t2.price
from table1 t1
inner join table2 t2
on t1.apples=t2.apples
Pretty simple stuff. Drop me a comment if you have any questions.