如何在mysql的UDF中创建两个循环

类似于，我想计算由TITLE1和TITLE2组成的

mxn

矩阵的Levenshtein距离

我的Levenshtein函数工作正常，从这里开始： 但我的问题是如何在UDF中循环通过

mxn

结果应该是一个表，其中包含

m x n

行以及LD、TITLE1和TITLE2

我已经这样做了，但我总是会出错

     1338 Cursor Declaration after Handler Declaration

我的UDF如下所示：

  BEGIN  
       DECLARE bDone INT;
       DECLARE bDone1 INT;

       DECLARE var2 varCHAR(255);    -- or approriate type
       DECLARE Var1 INT;
       DECLARE c1Var1 VARCHAR(250);

       DECLARE curs CURSOR FOR  SELECT recid as BIOTIrecid, replace(replace(BIOGRAPHYTITLE," [in SCOPUS]",""),"[SIMILAR]","") as bioti FROM BIO ;
       DECLARE CONTINUE HANDLER FOR NOT FOUND SET bDone = 1;
       DECLARE curs1 CURSOR FOR  SELECT trim(concat(scopus.Titel," ",scopus.Untertitel)) as scopusti FROM scopus ;
       DECLARE CONTINUE HANDLER FOR NOT FOUND SET bDone = 1;

       DROP  TABLE IF EXISTS LDResults;
        CREATE TABLE `LDResults` (
           `BIOGRAPHYTITLE` varchar(255) DEFAULT NULL,
           `recid` int(11) NOT NULL AUTO_INCREMENT,
           `BIOTIrecid` int(11) default NULL,
           `LD` varchar(255) DEFAULT NULL,
           `ScopusTI` varchar(255) DEFAULT NULL,
           PRIMARY KEY (`recid`)
        ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

        OPEN curs1;

        SET bDone1 = 0;
        #---------------- run all rows for scopusti
        REPEAT
            FETCH curs1 into c1var1;

        #-----------------------------------------
            OPEN curs;

            SET bDone = 0;
            #----- run all COLUMNs for biographytitle
            REPEAT
                FETCH curs INTO var1, var2;
                INSERT INTO LDResults (`BIOGRAPHYTITLE`, `BIOTIrecid`, `LD`, `ScopusTI`) VALUES (var2, var1, LEVENSHTEIN(var2,c1var1), c1var1);
            UNTIL bDone END REPEAT;
        #--------------------------------------------
        CLOSE curs;

        UNTIL bDone1 END REPEAT;


       CLOSE curs1;
       SELECT * FROM LDResults;
     END

我解决这个问题的方法是复杂的还是可以用更快更好的方法解决

谢谢你的建议

编辑： 我可以在这里用一个计数器：有什么评论吗

     BEGIN  
        -- DECLARE bDone INT;
        -- DECLARE bDone1 INT;

        DECLARE i INT;

       DECLARE var2 varCHAR(255);    -- or approriate type
       DECLARE Var1 INT;
       DECLARE cVar1 VARCHAR(250);

       DECLARE curs1 CURSOR FOR  SELECT trim(concat(t.Titel," ",t.Untertitel)) as scopusti FROM tscopus t ;
       DECLARE curs CURSOR FOR  SELECT recid as BIOTIrecid, replace(replace(BIOGRAPHYTITLE," [in SCOPUS]",""),"[SIMILAR]","") as bioti FROM tBIO ;
       DECLARE CONTINUE HANDLER FOR NOT FOUND SET bDone = 1;
       #DECLARE curs1 CURSOR FOR  SELECT trim(concat(t.Titel," ",t.Untertitel)) as scopusti FROM tscopus t ;
       #DECLARE CONTINUE HANDLER FOR NOT FOUND SET bDone = 1;

       DROP  TABLE IF EXISTS LDResults;
        CREATE TABLE `LDResults` (
       `BIOGRAPHYTITLE` varchar(255) DEFAULT NULL,
       `recid` int(11) NOT NULL AUTO_INCREMENT,
       `BIOTIrecid` int(11) default NULL,
       `LD` varchar(255) DEFAULT NULL,
       `ScopusTI` varchar(255) DEFAULT NULL,
       PRIMARY KEY (`recid`)
        ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;


        OPEN curs1;
        SET i = 0;

        SET bDone1 = 0;
        -- ---------------- run all rows for scopusti
        REPEAT
            FETCH curs1 into cvar1;

         set i=(i+1);
        -- -----------------------------------------
            OPEN curs;

            SET bDone = 0;
            -- ----- run all COLUMNs for biographytitle
            REPEAT
                FETCH curs INTO var1, var2;
                INSERT INTO LDResults (`BIOGRAPHYTITLE`, `BIOTIrecid`, `LD`, `ScopusTI`) VALUES (var2, var1, LEVENSHTEIN(var2,cvar1), cvar1);
            UNTIL bDone END REPEAT;
        -- --------------------------------------------
        CLOSE curs;

        UNTIL (i >= 2) END REPEAT;


       CLOSE curs1;
       SELECT * FROM LDResults;
     END

---

我的意思是，您可以通过下一种方式来完成，在代码中使用无循环。按定义交叉联接返回两个表行结果的乘积。 因此，您可以使用此结果，并在进行一些数据操作后，将结果插入到新表中，如：

DROP  TABLE IF EXISTS LDResults;
CREATE TABLE `LDResults` (
   `BIOGRAPHYTITLE` varchar(255) DEFAULT NULL,
   `recid` int(11) NOT NULL AUTO_INCREMENT,
   `BIOTIrecid` int(11) default NULL,
   `LD` varchar(255) DEFAULT NULL,
   `ScopusTI` varchar(255) DEFAULT NULL,
   PRIMARY KEY (`recid`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

INSERT INTO LDResults (`BIOGRAPHYTITLE`, `BIOTIrecid`, `LD`, `ScopusTI`)
SELECT bioti, BIOTIrecid, LEVENSHTEIN(bioti,scopusti), scopusti
FROM (
    SELECT 
        replace(replace(BIO.BIOGRAPHYTITLE," [in SCOPUS]",""),"[SIMILAR]","") as bioti,
        BIO.recid as BIOTIrecid,
        trim(concat(scopus.Titel," ",scopus.Untertitel)) as scopusti 
    FROM scopus
    CROSS JOIN BIO
) tbl;