What is Aggregate Query and Polymorphic Query in Salesforce

Aggregate Query:-

It is use to find the aggregate result for a field. Below are few methods that are supported in Aggregate Query.

1. Count
2. Sum
3. Max
4. Min
5. AVG

Select Count(Id), AccountId From Contact Group By AccountId.

For Example:-

• Select Count(Id), Industry From Account Group By Industry
• Select SUM(Amount), AccountId, Account.Name From Opportunity Group By AccountId, Account.Name.
• Select Max(closeDate), Account.Name From Opportunity Group By Account.Name
• Aggregate query do not return after 2000 records
• While using Grop by Field in Select Statement either should be Group By OR Aggregated.
• To Find out the duplicate records based on a particular field. For example , external Id.
• Select AccountId From Contact Group By AccountId Having Count(Id) > 2
• Select Email, Count(Id) From Contact Group By Email Having Count(Email) > 1

Polymorphic Query:-

A Polymorphic relationship is one where the current object can be one of several object types depending on a related Events.

For Example:-

• Select Id, Subject, What.Type, Who.Type From Account Where What.Type='Account'
• Select Id, Subject, What.Type, Who.Type From Task Where What.Type='Account'

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