Inlist的绑定优化(书摘备查)

 -- 建立类型 CREATE OR REPLACE TYPE numtabletype AS TABLE OF NUMBER;

CREATE OR REPLACE TYPE vartabletype AS TABLE OF VARCHAR2 (1000);

-- 解析字符串 CREATE OR REPLACE FUNCTION str2numlist (p_string IN VARCHAR2)    RETURN numtabletype AS    v_str    LONG         DEFAULT p_string || ',';    v_n      NUMBER;    v_data   numtabletype := numtabletype (); BEGIN    LOOP       v_n := TO_NUMBER (INSTR (v_str, ','));       EXIT WHEN (NVL (v_n, 0) = 0);       v_data.EXTEND;       v_data (v_data.COUNT) := LTRIM (RTRIM (SUBSTR (v_str, 1, v_n - 1)));       v_str := SUBSTR (v_str, v_n + 1);    END LOOP;

   RETURN v_data; END;

CREATE OR REPLACE FUNCTION str2varlist (p_string IN VARCHAR2)    RETURN vartabletype AS    v_str    LONG            DEFAULT p_string || ',';    v_n      VARCHAR2 (2000);    v_data   vartabletype    := vartabletype (); BEGIN    LOOP       v_n := INSTR (v_str, ',');       EXIT WHEN (NVL (v_n, 0) = 0);       v_data.EXTEND;       v_data (v_data.COUNT) := LTRIM (RTRIM (SUBSTR (v_str, 1, v_n - 1)));       v_str := SUBSTR (v_str, v_n + 1);    END LOOP;

   RETURN v_data; END;

-- 绑定查询 SELECT /*+ ordered use_nl(a,u) */        ID, NAME, nick   FROM TABLE (str2numlist (:bind0)) a, users u  WHERE u.ID = a.COLUMN_VALUE;

SELECT /*+ leading(a) */        ID, NAME, nick   FROM users u  WHERE ID IN (SELECT *                 FROM TABLE (str2numlist (:bind0)) a);

SELECT /*+ index(u ind_users_id) */        ID, NAME, nick   FROM users u  WHERE ID IN (SELECT *                 FROM THE (SELECT CAST (str2numlist (:bind0) AS numtabletype)                             FROM DUAL)                WHERE ROWNUM < 1000);

本文参与腾讯云自媒体分享计划,欢迎正在阅读的你也加入,一起分享。

发表于

我来说两句

0 条评论
登录 后参与评论

相关文章

扫码关注云+社区