The from Clause

Use the from clause to specify the tables and views to use in a join statement. .

This is the clause that indicates to SAP ASE that a join is desired. You can list the tables or views in any order. The order of tables affects the results that appear only when you use select * to specify the select list.

At most, a query can reference 250 tables and 46 worktables (such as those created by aggregate functions). The 250-table limit includes:

Tables (or views on tables) listed in the from clause
Each instance of multiple references to the same table (self-joins)
Tables referenced in subqueries
Tables being created with into
Base tables referenced by the views listed in the from clause

The following example joins columns from the titles and publishers tables, doubling the price of all books published in California:

begin tran

update titles 
  set price = price * 2 
  from titles, publishers 
  where titles.pub_id = publishers.pub_id 
  and publishers.state = "CA"

rollback tran

Table or view names can be qualified by the names of the owner and database, and can be given correlation names for convenience. For example:

select au_lname, au_fname 
from pubs2.blue.authors, pubs2.blue.publishers 
where authors.city = publishers.city