Type of SOQL Query in Salesforce

There are two type SOQL Query in Salesforce:-

Child to Parent:-

• Sometime we want to fetch few fields of the parent record while working with child record then we go for child to parent query.
• For example, working with contacts records user need the Account Shipping Address then for this use case SOQL will Look like below.
• SELECT Id, Name, AccountId, Account.ShippingAddress From Contact.
• In the above SOQL Account is the Field Name for Lookup/Master Details on the Contacts (Child) Object.

Parent to Child (Inner Query):-

Why we use parent to child Inner Query?:-

• Whenever we want to retrieve the related/child record for particular parent record or set of parent record then use the concept of Inner Query.
• For example, we want to retrieve the Contacts Related to particular Account then we will use below SOQL.
• SELECT Id, Name, (Select Id, Name From Contacts ) From Account WHERE Id IN: accList.
• Here is the above Query Contacts is Relationship Name. For standared Object it will always will be the Plural label of object name. For example, Contact => Contacts, Case = > Cases, Opportunity => Opportunities.
• For Custom Objects, We will append__r which will represent the Relationship with Account then in the Inner Query it will be Books__r.

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