## Posts

Showing posts from April, 2023

### 20 Essential DAX Functions Every Data Analyst and Power BI Developer Should Know for a Successful Interview

1. SUM: The SUM function calculates the sum of a column or expression for the rows that meet a specified filter criteria. Total Sales Amount = SUM(Sales[Sales Amount]) In this example, the SUM function calculates the total sales amount for the Sales[Sales Amount] column in the sales table. 2. CALCULATE: The CALCULATE function modifies the filter context of a DAX expression by applying additional filter criteria. Total Sales Amount for 2022 = CALCULATE(SUM(Sales[Sales Amount]), Sales[Year] = 2022) In this example, the CALCULATE function calculates the total sales amount for the Sales[Sales Amount] column in the sales table, but only for the rows where the Sales[Year] column equals 2022. 3. FILTER: The FILTER function returns a table that contains a subset of the rows from a specified table that meet a specified filter criteria. Total Sales Amount by Category = SUMX( FILTER( Product, [Selected Category] = "All" ||

### Top 10 Interview Question For Data Analyst in 2023

1 What is the difference between INNER JOIN and OUTER JOIN in SQL? INNER JOIN returns only the matching rows from both tables, while OUTER JOIN returns all the rows from both tables, along with null values for non-matching rows. Example: sql SELECT * FROM table1 INNER JOIN table2 ON table1.id = table2.id; 2 What is a subquery in SQL? Provide an example. A subquery is a query that is nested within another query. It is used to retrieve data that will be used in the main query. Example: sql SELECT * FROM table1 WHERE id IN ( SELECT id FROM table2 WHERE column = 'value' ); 3 What is a view in SQL? Provide an example. A view is a virtual table that is based on the result of a SELECT statement. It is used to simplify complex queries and to provide a level of security by limiting access to certain data. Example: sql CREATE VIEW view1 AS SELECT column1, column2 FROM table1 WHERE column1 = 'value' ; 4 What is the difference between a clustered index and a