Variables and control flow in MySQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a variable in MySQL stored procedures?

A variable in MySQL stored procedures is a named memory location used to store data temporarily during the execution of the procedure. It helps hold values that can be changed and used in control flow statements.

beginner

How do you declare a variable inside a MySQL stored procedure?

You declare a variable using the DECLARE statement followed by the variable name and data type, for example: DECLARE myVar INT; This must be done at the beginning of the procedure block.

beginner

What is the purpose of the IF statement in MySQL?

The IF statement allows you to execute different blocks of code based on a condition. It helps control the flow by choosing which code runs depending on whether the condition is true or false.

intermediate

Explain the WHILE loop in MySQL stored procedures.

The WHILE loop repeats a block of code as long as a specified condition remains true. It is useful for running repetitive tasks until a condition changes.

intermediate

What is the difference between a local variable and a user-defined variable in MySQL?

A local variable is declared inside a stored procedure and only exists during its execution. A user-defined variable starts with @ and can be used outside procedures and persist for the session.

How do you assign a value to a variable inside a MySQL stored procedure?

A DECLARE variable_name = value;

B SET variable_name = value;

C ASSIGN variable_name TO value;

D DEFINE variable_name = value;

You assign values to variables using the SET statement, for example: SET myVar = 10;

Which keyword starts a conditional block in MySQL stored procedures?

A FOR

B CASE

C IF

D LOOP

The IF keyword starts a conditional block to execute code based on a condition.

What happens if the WHILE loop condition is false at the start?

A An error occurs.

B The loop runs infinitely.

C The loop runs once anyway.

D The loop does not run at all.

If the WHILE condition is false initially, the loop body does not execute.

Where must DECLARE statements appear in a MySQL stored procedure?

A At the beginning of the procedure block

B At the end of the procedure

C Anywhere in the procedure

D Outside the procedure

DECLARE statements must be at the start of the procedure block before any other statements.

Which symbol is used to start a user-defined variable in MySQL?

A @

B $

C #

D &

User-defined variables start with the @ symbol, like @myVar.

Describe how variables and control flow statements work together in a MySQL stored procedure.

Think about how you store values and decide what code runs next.

Explain the difference between DECLARE and SET statements in MySQL stored procedures.

One is for making space, the other is for putting things in that space.