Perficient Interview Questions, Process, and Tips

Rank and dense rank are used to assign a rank to each row in a result set based on the values in a specific column.

• Rank assigns unique ranks to each row, with gaps in the ranking sequence if there are ties.

• Dense rank assigns unique ranks to each row, with no gaps in the ranking sequence if there are ties.

• Rank and dense rank are commonly used in data analysis and reporting to identify top performers or outliers.

• Example:...read more

SCD stands for Slowly Changing Dimensions. There are three types of SCD: Type 1, Type 2, and Type 3.

• Type 1: Overwrite the old data with new data.

• Type 2: Create a new record for the new data and keep the old record.

• Type 3: Create a new column for the new data and keep the old column.