site:docs.oracle.com sql functions
--聚合函数
site:docs.oracle.com group by function
site:docs.oracle.com GROUP BY clause
site:docs.oracle.com WHERE Clause
site:docs.oracle.com ORDER BY clause
site:docs.oracle.com rownum
--列转行
site:docs.oracle.com listagg
site:docs.oracle.com table dual
site:docs.oracle.com select
site:docs.oracle.com v$version
site:docs.oracle.com JOIN operations