OK Smarty pantses
how about this:
table "customer_snapshot"
fields customer_surname, customer_dob, snapshot_date, customer_email(other fields...)
for the purposes of this exercise customer_surname, customer_dob and snapshot_date are a composite PK.
What I want to know is:
1) which customers exist today that didn't exist yesterday and
2) which customers existed yesterday that don't exist today and
3) which customers have changed their email addresses since yesterday.
DB: Sybase, Number of records in table - about 2.5 million.
how about this:
table "customer_snapshot"
fields customer_surname, customer_dob, snapshot_date, customer_email(other fields...)
for the purposes of this exercise customer_surname, customer_dob and snapshot_date are a composite PK.
What I want to know is:
1) which customers exist today that didn't exist yesterday and
2) which customers existed yesterday that don't exist today and
3) which customers have changed their email addresses since yesterday.
DB: Sybase, Number of records in table - about 2.5 million.
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