oracle 12c使用子查询保理子句与plsql声明

Question

我是子查询保理子句的忠实粉丝。

WITH t1 as (select 1 as id from dual) 
select * from t1; 

和Oracle 12c中现在包括在WITH子句的PL/SQL声明部分

WITH 
    FUNCTION with_function(p_id IN NUMBER) RETURN NUMBER IS 
    BEGIN 
    RETURN p_id; 
    END; 
SELECT with_function(id) 
FROM t1 
WHERE rownum = 1 

，但我似乎无法让他们一起工作这可能吗？

WITH t1 as (select 1 as id from dual) 
WITH FUNCTION with_function(p_id IN NUMBER) RETURN NUMBER IS 
    BEGIN 
    RETURN p_id; 
    END; 
SELECT with_function(id) 
FROM t1 
WHERE rownum = 1; 

Answer 1

请参考语法：
https://docs.oracle.com/database/121/SQLRF/statements_10002.htm#SQLRF01702

plsql_declarations

subquery_factoring_clause

正如你看到的，语法是：

WITH [ plsql_declarations ] [ subquery_factoring_clause ] 

这意味着，PL/SQL必须先走，然后SQL查询的休息，以这样的方式

WITH 
    FUNCTION with_function(p_id IN NUMBER) RETURN NUMBER IS 
    BEGIN 
    RETURN p_id; 
    END; 
t1 as (select 1 as id from dual) 
SELECT with_function(id) 
FROM t1 
WHERE rownum = 1;