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What can be used instead of GROUP BY?
SQL Sub-query as a GROUP BY and HAVING Alternative You can use a sub-query to remove the GROUP BY from the query which is using SUM aggregate function. There are many types of subqueries in Hive, but, you can use correlated subquery to calculate sum part.
Does GROUP BY remove duplicates in SQL?
The group by clause can also be used to remove duplicates. The go to solution for removing duplicate rows from your result sets is to include the distinct keyword in your select statement. It tells the query engine to remove duplicates to produce a result set in which every row is unique.
When to use distinct along with group by?
You would use this to return different levels of aggregation returned in a single row. The use case would be for when a single grouping would not suffice all of the aggregates needed. Thanks for contributing an answer to Stack Overflow!
Which is better group by or distinct clause?
There is no significantly difference between group by and distinct clause except the usage of aggregate functions. Both can be used to distinguish the values but if in performance point of view group by is better. When distinct keyword is used , internally it used sort operation which can be view in execution plan.
When to use distinct or group by in Teradata?
When you have many different values, the preaggregation step of GROUP BY is not very efficient. Teradata has to sort the data to remove duplicates. In this case, it may be better to the redistribution first, i.e. use the DISTINCT statement.
When to use group by and having clauses?
WHERE Clause can be utilized with SELECT, UPDATE, DELETE, and INSERT, whereas HAVING can be utilized only with SELECT statement. The normalized relational database breaks down the complex table into small tables, which helps you to eliminate the data redundancy, inconsistency and ensure there is no loss of information.