Fix a query that finds no rows

Debug it · Intermediate · 10 min · Runs in your Salesforce Developer org · Apex Path

Scenario. A screen shows the phone of the Account a caller names. It crashed for a caller whose Account had been renamed.

A lookup method works until an Account is missing, then throws List has no rows for assignment to SObject. Make it return null instead.

What you will learn

Assigning a query straight to one record is a gamble:

Account match = [SELECT Phone FROM Account WHERE Name = :name LIMIT 1];

When nothing matches, Apex throws List has no rows for assignment to SObject. There is no null to check. The safe shape is to query into a List, which is empty when nothing matches, and check isEmpty() before you read [0].

Gotcha. LIMIT 1 protects you from too many rows, not from zero rows.

The task

Fix phoneFor so it returns null when no Account has that name, instead of throwing.

Examples:

Account Northwind with Phone 555-0100 → 555-0100
no Account named Nobody → null
Account Quiet with no Phone → null

Requirements:

Query into a List<Account> instead of one Account.
Return null when the list is empty.
Return the Phone of the first match otherwise. Keep LIMIT 1.
Do not wrap the query in try and catch. Fix the cause, not the symptom.

Starter code

public class AS_1603269E2B24_AccountPhones {
    public static String phoneFor(String accountName) {
        Account match = [
            SELECT Phone
            FROM Account
            WHERE Name = :accountName
            LIMIT 1
        ];
        return match.Phone;
    }
}

When it passes

A matching Account gives its Phone. No match, a blank name, or a match with no Phone all give null, with no exception.

Try this drill free

You write the Apex yourself. ApexSensei runs it and tells you what passed and what did not.

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