Diagnosing duplicates
In this lesson, you learned how to use the ROW_NUMBER()
function. ROW_NUMBER()
returns a number which begins at 1 for the first row in every partition, and provides a sequential number for each row within the same partition.
Considering that the partition for the statistics_flight
table is formed by the columns airport_code
, carrier_code
, and registration_date
, can you guess what value will give the ROW_NUMBER()
function in the row_num
column for the last row?
|registration_code|airport_code|carrier_code|registration_date|canceled|on_time|row_num|
|-----------------|------------|------------|-----------------|--------|-------|-------|
|000000137 |MSP |EV |2014-01-01 |117 |369 |1 |
|000000138 |MSP |F9 |2014-01-01 |0 |60 |1 |
|000000139 |MSP |FL |2014-01-01 |8 |83 |1 |
|000000140 |MSP |MQ |2014-01-01 |20 |67 |1 |
|000000141 |MSP |OO |2014-01-01 |76 |1031 |1 |
|000000142 |MSP |OO |2014-01-01 |76 |1031 |2 |
|000000143 |MSP |OO |2014-01-01 |76 |1031 |???????|
This exercise is part of the course
Cleaning Data in SQL Server Databases
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