De-duplicating Rows
Often the need arises to locate and remove duplicated rows, or partially duplicated rows from a table. Queries using the DISTINCT keyword (or it’s synonym UNIQUE) will retrieve and display rows without duplicates. But actually identifying and then removing the unwanted duplicates within a table represents a different level of work, and is also likely to involve greater resource consumption. Continue…
Unpivoting Spreadsheets into Oracle
The premise is as follows: You’ve got useful data lying in an Excel or Google spreadsheet which you’d like translated into relational table(s). This is likely going to involve normalizing the denormalized spreadsheet data on the way into the database; you are going to end up with (and want) more rows in your table than the corresponding quantity within the spreadsheet. The SQL tool for this is the UNPIVOT keyword. Continue…