Can I use… window … as (<existing window name> …)

Definitions in the window clause can inherit declarations from previous window names of the same clause.

 SELECT COUNT(*) OVER tenant
      , SUM(x) OVER past
   FROM …
 WINDOW tenant AS (PARTITION BY …)
      , past AS (tenant ORDER BY …) 

The window name past inherits the partition by clause from tenant.

Related

• Other forms: over clause (inline), window clause

• Product specific clause: qualify.

Normative References

The window clause, including the ability to refer to existing window names, is defined in ISO/IEC 9075:2016-2 as part of optional feature T612.