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  • mysql自定义函数收集

    代码:

    查找字符串 in_string 中,存在多少个字符串 in_find_str

    delimiter $$
    DROP FUNCTION IF EXISTS `fn_findCharCount` $$
    CREATE FUNCTION fn_findCharCount
    (
    in_string VARCHAR(
    500), in_find_str VARCHAR(50) ) RETURNS INT BEGIN DECLARE tcount INT DEFAULT 0; DECLARE new_str VARCHAR(500); DECLARE scount INT; SET new_str = in_string; SELECT INSTR(new_str,in_find_str) INTO scount; WHILE scount>0 DO SET tcount = tcount+1; SELECT SUBSTRING(new_str FROM (scount+1) FOR CHAR_LENGTH(new_str)) INTO new_str; SELECT INSTR(new_str,in_find_str) INTO scount; END WHILE; RETURN(tcount); END$$ delimiter ;

    产生范围在 start_num 和 end_num 之间的随机数:

    delimiter $$
    DROP FUNCTION IF EXISTS `fn_rand_num` $$
    CREATE FUNCTION fn_rand_num (
        start_num INTEGER,
        end_num INTEGER
    ) RETURNS INTEGER
    BEGIN
        RETURN FLOOR(start_num + RAND() * (end_num - start_num + 1));
    END$$;
    delimiter ;

    删除函数:DROP FUNCTION IF EXISTS `fn_findCharCount`;

    执行函数:select fn_findCharCount('abcd','b');

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  • 原文地址:https://www.cnblogs.com/xsj1989/p/7227328.html
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