4.3.4.Weekly challenge 3 - sj50179/Google-Data-Analytics-Professional-Certificate GitHub Wiki

Weekly challenge 3

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Question 1

Data analysts choose SQL for which of the following reasons? Select all that apply.

  • SQL is a well-known standard in the professional community
  • SQL can handle huge amounts of data
  • SQL is a powerful software program
  • SQL is a programming language that can also create web apps

Correct. Data analysts choose SQL because it is a well-known standard in the professional community. SQL can also handle huge amounts of data.

Question 2

In which of the following situations would a data analyst use spreadsheets instead of SQL? Select all that apply.

  • When using a language to interact with multiple database programs
  • When working with a small dataset
  • When working with a dataset with more than 1,000,000 rows
  • When visually inspecting data

Correct. An analyst would choose to use spreadsheets instead of SQL when visually inspecting data or working with a small dataset.

Question 3

A data analyst creates many new tables in their company’s database. When the project is complete, the analyst wants to remove the tables so they don’t clutter the database. What SQL commands can they use to delete the tables?

  • DROP TABLE IF EXISTS
  • INSERT INTO
  • CREATE TABLE IF NOT EXISTS
  • UPDATE

Correct. The analyst can use the DROP TABLE IF EXISTS query to delete the tables so they don’t clutter the database.

Question 4

A data analyst is cleaning customer data for an online retail company. They are working with the following section of a database:

The analyst wants to retrieve the first two letters of each state so that all the entries are consistent and only contain 2 letters. What is the correct SQL clause to retrieve the first two letters of each state?

  • DISTINCT(state, 1, 2)
  • SUBSTR(state, 1, 2)
  • WHERE(state, 1, 2)
  • LENGTH(state, 1, 2)

Correct. The correct clause is SUBSTR(state, 1, 2)*.*

Question 5

A data analyst is cleaning a dataset. They find data entries with extra spaces. What SQL function can the analyst use to eliminate the extra spaces for consistency?

  • SUBSTR
  • CAST
  • TRIM
  • LENGTH

Correct. The analyst can use the TRIM function to eliminate the extra spaces for consistency.

Question 6

In SQL databases, what data type refers to a number that contains a decimal?

  • Integer
  • Boolean
  • String
  • Float

Correct. In SQL databases, the float data type refers to a number that contains a decimal.

Question 7

A data analyst is working with product sales data. They import new data into a database. The database recognizes the data for product price as text strings. What SQL function can the analyst use to convert text strings to floats?

  • TRIM
  • CAST
  • SUBSTR
  • LENGTH

Correct. The analyst can use the CAST function to convert text strings to floats.

Question 8

A data analyst is cleaning survey data. The results for an optional question contain many nulls. What function can the analyst use to eliminate the null values from the results?

  • CONCAT
  • COALESCE
  • CAST
  • LENGTH

Correct. The analyst can use the COALESCE function to eliminate the null values from the results.