Controlling Code with If/Then/Else

1. The Core of Decision Making: If...Then

At its most basic, a conditional statement checks if a certain condition is true. If it is, VBA executes a specific block of code. The syntax for this is straightforward:

If [condition] Then
    ' Code to run if the condition is True
End If

The [condition] is an expression that evaluates to either True or False. This is usually a comparison between a variable and a value. To build these conditions, we use comparison operators. Since you're building your Excel knowledge from the ground up, let's explicitly define these operators:

Let's see this in a simple macro. Imagine you want to check if a sales total, stored in a variable, has met a target.

Option Explicit

Sub CheckSalesTarget()
    Dim salesTotal As Double
    salesTotal = 12500

    If salesTotal > 10000 Then
        MsgBox "Congratulations! You've met the sales target."
    End If
End Sub

If you run this code, the message box will appear because the condition 12500 > 10000 is true. If you change salesTotal to 9500, the macro will run but do nothing, because the code inside the If...End If block is skipped.

2. Providing an Alternative Path with Else

What if you want something to happen when the condition is false? This is where the Else statement comes in. It provides an alternative block of code to run.

The structure expands like this:

If [condition] Then
    ' Code to run if the condition is True
Else
    ' Code to run if the condition is False
End If

Let's improve our sales-checking macro:

Sub CheckSalesTarget_WithElse()
    Dim salesTotal As Double
    salesTotal = 9500

    If salesTotal > 10000 Then
        MsgBox "Congratulations! You've met the sales target."
    Else
        MsgBox "Target not yet met. Keep pushing!"
    End If
End Sub

Now, no matter the value of salesTotal, the user gets a relevant message. This branching logic is fundamental to programming. The flowchart below illustrates this concept visually.

3. Handling Multiple Conditions with ElseIf

Often, you'll need to check for more than two possibilities. For instance, you might want to grade a score as "Excellent", "Good", or "Needs Improvement". You could nest If statements inside each other, but that gets messy. A much cleaner way is to use ElseIf.

The ElseIf statement allows you to add more conditions to the chain. VBA checks each condition in order, from top to bottom. As soon as it finds a condition that is True, it executes the corresponding code block and then immediately jumps to End If, skipping all other checks.

The full structure looks like this:

If [condition 1] Then
    ' Code for condition 1
ElseIf [condition 2] Then
    ' Code for condition 2
ElseIf [condition 3] Then
    ' Code for condition 3
Else
    ' Code to run if NONE of the above conditions are true
End If

The final Else is optional but serves as a useful "catch-all" for any cases you didn't explicitly check for.

To see a practical demonstration of building up these structures, let's turn to a video.

4. Creating Complex Conditions with And and Or

Sometimes a single comparison isn't enough. You might need to check if a value falls within a range, or if one of several possibilities is true. For this, we use the logical operators And and Or.

• And: Requires that all connected conditions are true.
  Example: If score >= 80 And score < 90 Then ... (This is true only for scores from 80 up to 89).
• Or: Requires that at least one of the connected conditions is true.
  Example: If dayOfWeek = "Saturday" Or dayOfWeek = "Sunday" Then ... (This is true for either weekend day).

The following guide provides clear examples and truth tables that explain how these operators work.

5. A Practical Application: Categorizing Data

Now, let's tie everything together. A common task in data analysis is to loop through a list of items and categorize each one based on its value. In the next lesson, we will formally cover loops, but seeing an If statement inside one now will show you its true power.

The video you watched earlier contains a perfect example of this. You'll see how to combine a loop with an If...ElseIf...Else structure to apply conditional logic to a whole range of cells at once.

This process—looping through data and using If statements to process each piece—is a pattern you will use constantly as a VBA developer. The animated example below shows the exact same concept, categorizing products based on price.

Conclusion

Today, you've unlocked one of the most powerful features in programming. By mastering If...Then...Else statements, you've given your macros the ability to think and react, transforming them from simple scripts into dynamic and intelligent tools.

Key Takeaways:

• The If...Then...End If block executes code only when a condition is true.
• Else provides an alternative code block to run when the If condition is false.
• ElseIf allows you to test a series of ordered conditions, making your logic more sophisticated. VBA executes the code for the first true condition it finds and then exits the block.
• Logical operators And (all conditions must be true) and Or (at least one condition must be true) let you build complex conditional checks.

In this lesson, you got a preview of how powerful If statements become when placed inside a loop. In our next session, we will dive deep into that topic, formally learning how to use the For Each loop to efficiently iterate over collections of cells, worksheets, or other objects.