表函數可接受查詢語句或游標作為輸入參數，并可輸出多行數據。該函數可以平行執行，并可持續輸出數據流，被稱作管道式輸出。應用表函數可將數據轉換分階段處理，并省去中間結果的存儲和緩沖表。

1。 用游標傳遞數據
利用游標 REF CURSOR 可將數據集(多行記錄)傳遞到PL/SQL函數：
SELECT
FROM TABLE (myfunction (CURSOR (SELECT
FROM mytab)));
2。 利用兩個實體化視圖(或表)作為樣板數據
CREATE MATERIALIZED VIEW sum_sales_country_mv
BUILD IMMEDIATE
REFRESH COMPLETE
ENABLE QUERY REWRITE
AS
SELECT SUBSTR (s。calendar_month_desc， 1， 4) YEAR， c。country_id country，
SUM (sum_amount_sold) sum_amount_sold
FROM sum_sales_month_mv s， customers c
WHERE s。cust_id ＝ c。cust_id
AND c。country_id IN (‘US‘， ‘UK‘， ‘FR‘， ‘ES‘， ‘JP‘， ‘AU‘)
GROUP BY SUBSTR (s。calendar_month_desc， 1， 4)， c。country_id;

CREATE MATERIALIZED VIEW sum_es_gend_mv
BUILD DEFERRED
REFRESH FAST
ENABLE QUERY REWRITE
AS
SELECT SUBSTR (s。calendar_month_desc， 1， 4) YEAR，
s。calendar_month_desc cal_month， c。cust_gender，
SUM (sum_amount_sold) sum_amount_sold
FROM sum_sales_month_mv s， customer c
WHERE s。cust_id ＝ c。cust_id
AND c。country_id ＝ ‘ES‘
AND sunstr (s。calendar_month_desc， 1， 4) ＝ ‘2000‘
GROUP BY SUBSTR (s。calendar_month_desc， 1， 4)，
s。calendar_month_desc，
c。cust_gender;
3。 定義對象類型和基于對象類型的表類型
定義對象類型并且為進一步引用做好準備。
(1)定義對象類型：TYPE sales_country_t
CREATE TYPE sales_country_t AS OBJECT (
YEAR VARCHAR2 (4)，
country CHAR (2)，
sum_amount_sold NUMBER
);
(2)定義表類型：TYPE SUM_SALES_COUNTRY_T_TAB
CREATE TYPE sum_sales_country_t_tab AS TABLE OF sales_country_t;
(3)定義對象類型：TYPE sales_gender_t
CREATE TYPE sales_gender_t AS OBJECT (
YEAR VARCHAR2 (4)，
country_id CHAR (2)，
cust_gender CHAR (1)，
sum_amount_sold NUMBER
);
(4)定義表類型：TYPE SUM_SALES_GENDER_T_TAB
CREATE TYPE sum_sales_gender_t_tab AS TABLE OF sales_gender_t;
(5)定義對象類型：TYPE sales_roll_t
CREATE TYPE sales_roll_t AS OBJECT (
channel_desc VARCHAR2 (20)，
country_id CHAR (2)，
sum_amount_sold NUMBER
);
(6)定義表類型：TYPE SUM_SALES_ROLL_T_TAB
CREATE TYPE sum_sales_roll_t_tab AS TABLE OF sales_roll_t;
(7)檢查一下建立的類型
SELECT object_name， object_type， status
FROM user_objects
WHERE object_type ＝ ‘TYPE‘;
4。 定義包：Create package and define REF CURSOR
CREATE OR REPLACE PACKAGE cursor_pkg
IS
TYPE sales_country_t_rec IS RECORD (
YEAR VARCHAR (4)，
country CHAR (2)，
sum_amount_sold NUMBER
);

TYPE sales_gender_t_rec IS RECORD (
YEAR VARCHAR2 (4)，
country_id CHAR (2)，
cust_gender CHAR (1)，
sum_amount_sold NUMBER
);

TYPE sales_roll_t_rec IS RECORD (
channel_desc VARCHAR2 (20)，
country_id CHAR (2)，
sum_amount_sold NUMBER
);

TYPE sales_country_t_rectab IS TABLE OF sales_country_t_rec;

TYPE sales_roll_t_rectab IS TABLE OF sales_roll_t_rec;

TYPE strong_refcur_t IS REF CURSOR
RETURN sales_country_t_rec;

TYPE row_refcur_t IS REF CURSOR
RETURN sum_sales_country_mv%ROWTYPE;

TYPE roll_refcur_t IS REF CURSOR
RETURN sales_roll_t_rec;

TYPE refcur_t IS REF CURSOR;
END corsor_pkg;

5。 定義表函數
(1)定義表函數：FUNCTION Table_Ref_Cur_Week
CREATE OR REPLACE FUNCTION table_ref_cur_week (cur CURSOR。refcur_t)
RETURN sum_sales_country_t_tab
IS
YEAR VARCHAR (4);
country CHAR (2);
sum_amount_sold NUMBER;
objset sum_sales_country_t_tab ：＝ sum_sales_country_t_tab ();
i NUMBER ：＝ 0;
BEGIN
LOOP
－－ Fetch from cursor variable
FETCH cur
INTO YEAR， country， sum_amount_sold;

EXIT WHEN cur%NOTFOUND;
－－ exit when last row is fetched
－－ append to collection
i ：＝ i + 1;
objset。EXTEND;
objset (i) ：＝ sales_country_t (YEAR， country， sum_amount_sold);
END LOOP;

CLOSE cur;

RETURN objset;
END;
/
(2)定義表函數：FUNCTION Table_Ref_Cur_Strong
CREATE OR REPLACE FUNCTION table_ref_cur_strong (cur cursor_pkg。strong_refcur_t)
RETURN sum_sales_country_t_tab PIPELINED
IS
YEAR VARCHAR (4);
country CHAR (2);
sum_amount_sold NUMBER;
i NUMBER ：＝ 0;
BEGIN
LOOP
FETCH cur
INTO YEAR， country， sum_amount_sold;

EXIT WHEN cur%NOTFOUND; －－ exit when last row fetched
PIPE ROW (sales_country_t (YEAR， country， sum_amount_sold));
END LOOP;

CLOSE cur;

RETURN;
END;
/
(3)定義表函數：FUNCTION Table_Ref_Cur_row
CREATE OR REPLACE FUNCTION table_ref_cur_row (cur cursor_pkg。row_refcur_t)
RETURN sum_sales_country_t_tab PIPELINED
IS
in_rec cur%ROWTYPE;
out_rec sales_country_t ：＝ sales_country_t (NULL， NULL， NULL);
BEGIN
LOOP
FETCH cur
INTO in_rec;

EXIT WHEN cur%NOTFOUND; －－ exit when last row is fetched
out_rec。YEAR ：＝ in_rec。YEAR;
out_rec。country ：＝ in_rec。country;
out_rec。sum_amount_sold ：＝ in_rec。sum_amount_sold;
PIPE ROW (out_rec);
END LOOP;

CLOSE cur;

RETURN;
END;
/
(4)定義表函數：FUNCTION Gender_Table_Ref_Cur_Week
CREATE OR REPLACE FUNCTION gender_table_ref_cur_week (cur cursor_pkg。refcur_t)
RETURN sum_sales_gender_t_tab
IS
YEAR VARCHAR2 (4);
country_id CHAR (2);
cust_gender CHAR (1);
sum_amount_sold NUMBER;
objset sum_sales_gender_t_tab ：＝ sum_sales_gender_t_tab ();
i NUMBER ：＝ 0;
BEGIN
LOOP
FETCH cur
INTO YEAR， country_id， cust_gender， sum_amount_sold;

EXIT WHEN cur%NOTFOUND; －－ exit when last row is fetched
i ：＝ i + 1;
objset。EXTEND;
objset (i) ：＝
sum_sales_gender_t (YEAR， country_id， cust_gender， sum_amount_sold);
END LOOP;

CLOSE cur;

RETURN objset;
END;
/

6。 調用表函數
下列 SQL 查詢語句調用已被定義的表函數。
SELECT
FROM TABLE (table_ref_cur_week (CURSOR (SELECT
FROM sum_sales_country_mv)));

SELECT
FROM TABLE (table_ref_cur_strong (CURSOR (SELECT
FROM sum_sales_country_mv)));

SELECT
FROM TABLE (table_ref_cur_row (CURSOR (SELECT
FROM sum_sales_country_mv)));

SELECT
FROM TABLE (table_ref_cur_week (CURSOR (SELECT
FROM sum_sales_country_mv
WHERE country ＝ ‘AU‘)));

總結

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