SQL Server multi-table query

1. Same-Library operations
   Select a. Column name 1,b. Column name 2,a. Column name 3 from table name 1 as a
   Join table Name 2 as B
   On a. Association field =b. Associated Fields

2. Different library operations
   Select a. Column name 1,b. Column name 2,a. Column Name 3 from library name 1.dbo. Table Name 1 as a
   Join library name 2.dbo. Table Name 2 as B
   On a. Association field =b. Associated Fields

3. 2 Tables above the multi-table connection: The first two connections and then the third connection, go down, such as
   Select a. Column name 1,b. Column name 2,a. Column name 3 from table name 1 as a
   Join table Name 2 as B
   On a. Association field =b. Associated Fields
   Join table name 3 as C
   On a. Association field =c. Associated Fields

SQL Server multi-table query