將SQL查詢保存到變量

Question

我寫了一個PL/PgSQL觸發器，我需要將查詢（實際上是結果集）保存到變量中。 見下文：

DECLARE 
    __query record; 
    r record; 
BEGIN 
    __query := (SELECT * FROM posts); 
    FOR r IN __query LOOP 
     -- do something with the row data 
    END LOOP; 

    RETURN NEW; 
END; 

我應該使用哪種類型的數據查詢本身？

我猜record是不適合的數據類型，應該在循環週期本身（用於r var）。

Answer 1

如果你的意思是你想通過查詢循環作爲一個字符變量，那麼你可以做這樣的：

DECLARE 
    _query : text; 
    r : record; 
BEGIN 
    _query := 'SELECT * FROM posts'; 

    FOR r IN EXECUTE _query LOOP 
     -- do stuff 
    END LOOP; 

    RETURN new; 
END; 

Answer 2

DECLARE 

    CURSOR cursor is (select * from posts); 
    r  record; 
BEGIN 

FOR cursor_rec in cursor LOOP 
    ... 
END LOOP; 

Answer 3

DECLARE 

    cursor c is select * from posts; 
    -- r record; you don't need to declare this variable 
BEGIN 
    FOR c_rec in c LOOP 
     ... 
     ... 
     ... 
    END LOOP; 
END; 

此代碼對Oracle PL-SQL