Get Row Size in SQL Server

I don't know if there's a built-in storedproc or function to determine each row size. Here's one way to do it. Get all column names and add each column's data length.

declare @cs varchar(8000);

select @cs = coalesce(@cs + ' + DATALENGTH(' + column_name + ')', 'DATALENGTH(' + column_name + ')')
from INFORMATION_SCHEMA.COLUMNS i where TABLE_NAME = 'Members';

declare @qry nvarchar(4000);

set @qry = 'select Length = ' + @cs + ', * from members ';
select @qry;
exec sp_executesql @qry;

Length  MemberID  LoginName    ReputationPoints
16      1         John         1
16      2         Paul         1
20      3         George       1
18      4         Ringo        1

Clean the table before deleting duplicates

Clean foreign tables and delete duplicates in referenced table, 8 steps

Test database tables:

create table item
(
item_id serial not null,
item text not null,
constraint pk_item primary key(item_id),
constraint uk_item unique (item)
);

   
create table purchased
(
purchased_id serial not null,
item_id int not null,
qty int not null,
constraint pk_purchased primary key(purchased_id),
constraint fk_purchased__item foreign key(item_id) references item(item_id) 
);

Test data:

insert into item (item) values
('cpu'),
('keyboard'),
('keyboard '),
('mouse');

insert into purchased(item_id,qty) values
(1,2),
(2,26),
(3,19),
(4,51),
(3,5);