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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   |???????|

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Cleaning Data in SQL Server Databases

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