and the below queries using professional principles and st…

and the below queries using professional principles and standards: A set of SQL Statements that returns all rows and all data for each table in your database Two SQL Statements that return a subset of columns and a subset of rows using the WHERE clause

Answer

In order to accomplish the first task of retrieving all rows and all data from each table in a database using SQL statements, you can employ the SELECT statement combined with the asterisk (*) as a wildcard symbol.

The SQL statement for this task would be as follows:

SELECT * FROM table_name;

Where “table_name” should be replaced with the actual name of each table in the database. By using the asterisk symbol in the SELECT statement, you are instructing the database to retrieve all columns from the specified table. The result of executing this statement would be a result set containing all the rows and all the data from each table in the database.

For the second task of retrieving a subset of columns and rows using the WHERE clause, you can further refine the SELECT statement to specify the desired columns and add conditions to filter the rows based on specific criteria.

The SQL statement for this task would be structured as follows:

SELECT column1, column2, … FROM table_name WHERE condition;

The “column1, column2, …” section represents the specific columns you want to retrieve, separated by commas. Again, you would replace “table_name” with the actual name of the table you are querying. The “condition” section is where you would define the criteria to filter the rows.

There are various operators that can be used in the WHERE clause to define the conditions, such as equality (=), comparison (<, >, <=, >=), and logical operators (AND, OR). The condition can involve a single column or multiple columns, depending on your requirements.

For example, if you wanted to retrieve only the “name” and “age” columns from a table called “customers” where the age is greater than 25, the SQL statement would look like this:

SELECT name, age FROM customers WHERE age > 25;

Executing this statement would return a result set containing only the rows where the age is greater than 25, with only the “name” and “age” columns included.

These SQL statements adhere to professional principles and standards, providing a concise and accurate approach to retrieve all rows and all data for each table, as well as a subset of columns and rows using the WHERE clause. By following these principles, you ensure efficiency and maintainability in your database querying process.