You must enter the ALL keyword in a group function to include all duplicate values. The AVG function can be used to find the average calculated difference between two dates. The MIN and MAX functions can be used on VARCHAR2 columns. All of the above...
rows after grouping. Unlike HAVING clause, the WHERE clause cannot contain aggregate functions. 13.What is Join? Ans: An SQL Join is used to combine data from two or more tables, based on a common field between them. For example, consider the following two tables. Student Table EnrollNo S...
There you have it: the five most popular SQL aggregate functions showcased on three medium-level interview questions. It’s not that difficult for a crucial SQL concept, is it? These three questions are good examples of what you can expect from the job interview. As you’ve seen, the SQL...
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Aggregate functions in SQL provide insights into the data within a database. For example, AVG calculates the average value of a column in a database. There are five primary aggregate functions: MIN (finds the minimum), MAX (finds the maximum), COUNT (counts the number of rows), SUM (add...
38. What are the TRUNCATE, DELETE and DROP statements? 39. What is the difference between DROP and TRUNCATE statements? 40. What is the difference between DELETE and TRUNCATE statements? 41. What are Aggregate and Scalar functions? PostgreSQL Interview Questions SQL MCQ Learn...
30. What are aggregate functions in SQL? An aggregate function performs a calculation on a set of values and returns a single value summarizing the background. SQL’s three most common aggregate functions are COUNT, SUM, and AVG. COUNT - Returns the number of items of a group. SUM - Ret...
How will you create your aggregate function using PostgreSQL? Let us consider that we have two tables say Employee and Department with the below data. /* Employee Table(tblEmployee) */ DeptId EmpName --- --- 1 Shashi Bhushan 1 Deepak Singh...
Explain the concept of window functions in PySpark and provide an example. PySpark Window functions allow us to apply operations across a window of rows returning a single value for every input row. We can perform ranking, analytics, and aggregate functions. ...
JOIN:Combines rows from multiple tables based on a related column and executes in one step. 32. Explain the difference between GROUP BY and DISTINCT. Answer: GROUP BY: Used to aggregate rows into groups based on one or more columns. It is often used with aggregate functions (like COUNT()...