In a distributed environment, views can improve efficiency by reducing the amount of data transferred over the network, thus reducing network traffic. 

User-defined functions in DB2 enable developers to encapsulate complex calculations into reusable components. This promotes code reuse, simplifies maintenance, and enhances readability. These functions can be easily integrated into SQL queries, allowing developers to perform custom calculations efficiently within the reporting system. 

In a LEFT JOIN, the data from the left table (first table in the JOIN statement) is retained, even if there are no matching rows in the right table. This ensures that all rows from the left table are included in the result set. 

A view in DB2 provides a virtual table that presents data from one or more tables in a customized format. Views can be used to simplify complex data structures, hide sensitive information, and restrict access to certain columns or rows. They enable users to query and manipulate data without directly accessing the underlying tables, enhancing data security and abstraction. 

Views in DB2 can simplify complex aggregation operations by predefining calculations or summaries, which can then be accessed as if they were a single table, thus simplifying query construction and improving query performance. 

Analyzing data distribution and access patterns helps in understanding the characteristics of the data and how it's accessed, which can guide the selection of the appropriate compression type. Randomly selecting a compression type may lead to suboptimal results. Choosing the same compression type used by other databases might not consider the specific requirements and characteristics of DB2. Consulting with IBM support or community forums can provide valuable insights but may not be as effective as analyzing the data directly. 

The first step in troubleshooting a synchronization issue between the primary and standby servers is to check the network connectivity between them. This involves verifying that both servers can communicate with each other over the network and ensuring that there are no firewall rules blocking the communication. Once network connectivity is confirmed, further investigation can be done to identify and resolve any configuration or software issues causing the synchronization problem. 

Instance creation in DB2 installation facilitates managing multiple database environments on the same server, providing separation for better management, establishing security parameters, and configuring database connections. 

In an Entity-Relationship Diagram (ERD), relationships signify the associations between entities. They define how entities are connected or related to each other in the database schema. These relationships are crucial for understanding the structure of the database and how data is organized. By establishing relationships, it becomes easier to maintain data integrity and establish constraints such as referential integrity. Understanding relationships aids in designing efficient database schemas and querying data effectively. 

Normalization in DB2 refers to the process of organizing data to minimize redundancy. This involves breaking down large tables into smaller ones and linking them through relationships, reducing data duplication and improving overall data integrity.