SQL How UPDATE command works -


how update command in sql work?
have table 3 columns a,b,c primary key.
values in table (1,2,3),(2,4,5).
suppose want update tuple , set value of column c 4 values of 1.
tuple (1,2,3) deleted , new tuple inserted ?
or values 1,2 kept constant 3 deleted , 4 inserted ?

this should edit table entry not adding new tuple table

update tablename set c='4' a='1'

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