This is for MySQL for AdventureWorks2017 Database

This will not use a subquery. Use a CASE expression to put the employees into groups by Age as of Jan 1, 2019. The groups will be

Table Human Resources.Employee (290 rows) Employee information such as salary, department, and title. Default int X Column Data Type Identity Nullable PK, FK Business EntityID Primary key for Employee records. Foreign key to Business Entity.Business EntityID. UK NationalIDNumber nvarchar(15) Unique national identification number such as a social security number. UK LoginID nvarchar(256) Network login. Organization Node hierarchyid Where the employee is located in corporate hierarchy. OrganizationLevel smallint The depth of the employee in the corporate hierarchy. JobTitle nvarchar(50) Work title such as Buyer or Sales Representative. Birth Date date Date of birth MaritalStatus nchar(1) M = Married, S = Single Gender nchar(1) M = Male, F = Female HireDate date Table Human Resources.Employee (290 rows) Employee information such as salary, department, and title. Default int X Column Data Type Identity Nullable PK, FK Business EntityID Primary key for Employee records. Foreign key to Business Entity.Business EntityID. UK NationalIDNumber nvarchar(15) Unique national identification number such as a social security number. UK LoginID nvarchar(256) Network login. Organization Node hierarchyid Where the employee is located in corporate hierarchy. OrganizationLevel smallint The depth of the employee in the corporate hierarchy. JobTitle nvarchar(50) Work title such as Buyer or Sales Representative. Birth Date date Date of birth MaritalStatus nchar(1) M = Married, S = Single Gender nchar(1) M = Male, F = Female HireDate date