3.7.2 Structured Query Language (SQL)

• A column in a relational database table defines the type of data stored in each row
• Relational databases use a structured, tabular format to organize data


  True
• Match the SQL statement with its description:

  SELECT ↔️ Retrieves specific columns

  FROM ↔️ Specifies the table

  WHERE ↔️ Filters data based on a condition
• A table in a relational database contains related data in rows and columns


  True
• SQL syntax is fundamental for querying and manipulating relational databases


  True
• A row in a table represents a single record


  True
• The SELECT, FROM, and WHERE statements are fundamental in SQL

  True
• What does the `SELECT` statement in SQL specify?

  Columns to retrieve
• How do you retrieve all columns from a table in SQL?

  SELECT *
• What does the `WHERE` clause in SQL allow you to do?

  Filter rows
• The `WHERE` clause is used to filter rows based on specified conditions.


  True
• Why is the `WHERE` clause considered a powerful tool in SQL?

  For filtering data
• The `ASC` keyword in SQL sorts data in ascending order.


  True
• Steps to retrieve and sort data using SQL

  1️⃣ Write the `SELECT` clause to specify columns

  2️⃣ Write the `FROM` clause to identify the table

  3️⃣ Use the `WHERE` clause to filter rows

  4️⃣ Use the `ORDER BY` clause to sort the result
• What is the purpose of the `LIMIT` clause in SQL?

  Limit row count
• Match the join type with its description:

  INNER JOIN ↔️ Returns rows where the join condition is met in both tables

  LEFT JOIN ↔️ Returns all rows from the left table and matching rows from the right

  RIGHT JOIN ↔️ Returns all rows from the right table and matching rows from the left
• What are the `UPDATE` and `INSERT` statements used for in SQL?

  Modify and add data
• The UPDATE statement is used to modify existing data
• Steps to update data in SQL using the UPDATE statement

  1️⃣ Specify the table name

  2️⃣ List columns and their new values using SET

  3️⃣ Filter rows to update using WHERE
• The INSERT statement is used to add new rows
• What does the VALUES clause in the INSERT statement provide?

  Values for each column
• A relational database stores data in tables
• A column in a relational database defines the type of data stored in each row.

  True
• What is the purpose of the WHERE clause in a SELECT statement?

  Filters data based on condition
• The WHERE clause is used to filter rows based on specified conditions
• The ORDER BY clause sorts rows in ascending order by default.


  True
• What is the result of the query `SELECT name, age FROM users ORDER BY age DESC;`?

  Users sorted by age descending
• To retrieve the top 5 users by age in descending order, you would use the LIMIT clause with the value 5
• What does the query `SELECT name, age FROM users ORDER BY age DESC LIMIT 5;` retrieve?

  Top 5 oldest users
• The ORDER BY clause is used with the LIMIT clause to sort the result set


  True
• Joining tables in SQL combines data based on a common column
• A LEFT JOIN returns all rows from the left table, plus matching rows from the right table


  True
• The UPDATE statement in SQL modifies existing data in a table
• The COUNT aggregate function in SQL counts the number of rows
• Match the aggregate function with its description:

  COUNT ↔️ Counts rows

  SUM ↔️ Calculates total

  AVG ↔️ Calculates average
• A relational database stores data in tables
• A relational database stores data in tables
• In a relational database, a column defines the type of data stored in each row
• What does the SELECT statement do in SQL?

  Retrieves specific columns
• What is the purpose of the WHERE clause in SQL?

  Filters data based on condition