FREE Back-End Development Technical (SQL) Questions and Answers
Which SQL command is employed to retrieve data from a database?
Explanation:
The SELECT statement is used to extract data from a database. It allows you to specify which columns you want to retrieve from a table and any filtering criteria or sorting instructions that you want to apply to the data.
How do you use SQL to select every column from the "Persons" table?
Explanation:
To select all columns from a table named "Persons" in SQL, you would use the following SELECT statement:
SELECT * FROM Persons;
How does one update data in a database using SQL?
Explanation:
The UPDATE statement is used to modify or update data in a database. It allows you to specify which table you want to update, which columns you want to modify, and the new values you want to set for those columns.
Which SQL statement is employed when new data is to be added to a database?
Explanation:
The INSERT INTO statement is used to insert new data into a database. It allows you to specify which table you want to insert data into and the values that should be inserted into each column.
How do you use SQL to choose the "FirstName" column from the "Persons" table?
Explanation:
To select a column named "FirstName" from a table named "Persons" in SQL, you would use the following SELECT statement:
SELECT FirstName FROM Persons;
How do you delete data from a database using SQL?
Explanation:
The DELETE statement is used to delete data from a database. It allows you to specify which table you want to delete data from and any filtering criteria to identify which rows should be deleted.