Data Analyst interview questions for Accenture are as follows :Â
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COUNT and COUNT DISTINCT in SQL?COUNT returns the total number of rows in a table or dataset, including duplicates. COUNT DISTINCT, however, returns the number of unique (distinct) values in a column, excluding duplicates.UNION and UNION ALL in SQL?UNION combines the results of two queries and removes duplicate rows, while UNION ALL combines the results without removing duplicates. UNION is used when we need unique results, while UNION ALL is used to retain all records, including duplicates.LEFT JOIN returns all rows from the left table and the matching rows from the right table. If no match is found, NULL values are returned for the right table. A FULL OUTER JOIN returns all rows from both tables, with NULLs in place where there are no matches.



