实例介绍
CREATE TABLE business_dates
(
location VARCHAR2 (20)
,business_date DATE
);
INSERT INTO business_dates (location, business_date)
VALUES ('Americas', DATE '2013-06-03');
INSERT INTO business_dates (location, business_date)
VALUES ('Europe', DATE '2013-06-04');
INSERT INTO business_dates (location, business_date)
VALUES ('Asia', DATE '2013-06-04');
CREATE OR REPLACE FUNCTION get_business_date (p_location VARCHAR2)
RETURN DATE
DETERMINISTIC
RESULT_CACHE
IS
v_date DATE;
dummy PLS_INTEGER;
BEGIN
DBMS_LOCK.sleep (5);
SELECT business_date
INTO v_date
FROM business_dates
WHERE location = p_location;
RETURN v_date;
END get_business_date;
/
CREATE TABLE transactions
AS
SELECT ROWNUM rn
,DECODE (MOD (ROWNUM - 1, 3), 0, 'Americas', 1, 'Europe', 'Asia')
location
,DECODE (MOD (ROWNUM - 1, 2)
,0, DATE '2013-06-03'
,DATE '2013-06-04')
transaction_date
FROM DUAL
CONNECT BY LEVEL <= 20;
SET TIMING ON
SELECT *
FROM transactions
WHERE transaction_date = get_business_date (location);
SET TIMING OFF
(
location VARCHAR2 (20)
,business_date DATE
);
INSERT INTO business_dates (location, business_date)
VALUES ('Americas', DATE '2013-06-03');
INSERT INTO business_dates (location, business_date)
VALUES ('Europe', DATE '2013-06-04');
INSERT INTO business_dates (location, business_date)
VALUES ('Asia', DATE '2013-06-04');
CREATE OR REPLACE FUNCTION get_business_date (p_location VARCHAR2)
RETURN DATE
DETERMINISTIC
RESULT_CACHE
IS
v_date DATE;
dummy PLS_INTEGER;
BEGIN
DBMS_LOCK.sleep (5);
SELECT business_date
INTO v_date
FROM business_dates
WHERE location = p_location;
RETURN v_date;
END get_business_date;
/
CREATE TABLE transactions
AS
SELECT ROWNUM rn
,DECODE (MOD (ROWNUM - 1, 3), 0, 'Americas', 1, 'Europe', 'Asia')
location
,DECODE (MOD (ROWNUM - 1, 2)
,0, DATE '2013-06-03'
,DATE '2013-06-04')
transaction_date
FROM DUAL
CONNECT BY LEVEL <= 20;
SET TIMING ON
SELECT *
FROM transactions
WHERE transaction_date = get_business_date (location);
SET TIMING OFF
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