Repeated record lookup methods in MS-SQLSERVER

Repeated record lookup methods in MS-SQLSERVER

 

1. Find records that are not repeated

Select distinct ID from Tab

 

2. Find duplicate records

Select ID from tab group by ID having count (*)> 1

 

The first method filters out duplicate records. What information is duplicated? No.

The second method is used to obtain Repeated Records.

 

Based on the above method, you can calculate records that are not repeated, as shown below:

 

1. Select count (ID) from (select distinct ID from tab)

 

2. Select count (distinct ID) from Tab

The two methods are feasible.