oracle while的用法示例分享

with  
alias_name1 as    (subquery1), 
alias_name2 as    (subQuery2), 
……  alias_nameN as    (subQueryN) 
select col1,col2…… col3
from alias_name1,alias_name2……,alias_nameN  

WITH  Q1 AS (SELECT 3 + 5 S FROM DUAL),
Q2 AS (SELECT 3 5 M FROM DUAL),
Q3 AS (SELECT S, M, S + M, S M FROM Q1, Q2) 
SELECT FROM Q3;

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