Data Migration Engineer Interview Questions and Answers

Query to find occurrence count of a character in a column of string datatype

• Use the function LENGTH to get the length of the string

• Use the function REPLACE to replace all characters except the one you want to count

• Use the function LENGTH again to get the count of the character

To delete duplicate records, use the DELETE statement with a subquery to identify and remove the duplicates.

• Identify the columns that contain duplicate data.

• Use the GROUP BY clause to group the data by those columns.

• Use the HAVING clause to filter the groups that have more than one row.

• Use a subquery to select the duplicate rows.

• Use the DELETE statement with the subquery to remove the duplicates.

Use SQL query with LENGTH and REPLACE functions to count number of A's in a word.

• Use LENGTH function to get the total length of the word.

• Use REPLACE function to remove all characters except 'A'.

• Subtract the length of the word after replacing all characters except 'A' from the original length to get the count of 'A's.

The count of occurrences of a specific character in a word.

• Iterate through each character in the word

• Check if the character is equal to 'a'

• If yes, increment a counter variable

• Return the counter variable as the count of occurrences