mysql字符串处理例子

DELIMITER //
DROP PROCEDURE IF EXISTS p_modify_year;
CREATE PROCEDURE p_modify_year()
BEGIN
    DECLARE tmpid int(8);
    DECLARE tmppcidd varchar(20);
    DECLARE tmpprocode varchar(20);
    DECLARE done INT DEFAULT FALSE;
    DECLARE cur CURSOR FOR SELECT product.id FROM product WHERE prostatus=0;    
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
    OPEN cur;
        
    myloop: LOOP
        
        FETCH cur INTO tmpid;
        
        IF done THEN
            LEAVE myloop;
        END IF;
        
        SELECT SUBSTRING(product.pcidd,2,2), product.procode INTO tmppcidd, tmpprocode FROM product WHERE id = tmpid;
        
　　　　　//pcidd和procode中第2、3位为16则替换成AU，其中procode可能为空。   
        IF tmppcidd = ‘16‘ THEN    
            UPDATE upe_product 
            set pcidd = CONCAT(SUBSTRING(pcidd, 1, 1), ‘AU‘, SUBSTRING(pcidd, 4, LENGTH(pcidd)+1)) 
            WHERE id = tmpid;
                    
            IF !ISNULL(tmpprocode) THEN    
                UPDATE product set procode = CONCAT(SUBSTRING(procode, 1, 1), ‘AU‘, SUBSTRING(procode, 4, LENGTH(procode)+1)) WHERE id = tmpid;
                
            END IF;
            
        END IF;
        
        SET tmpprocode = NULL;
        SET tmppcidd = NULL;
        
        SET done = FALSE;
        
    END LOOP;
    CLOSE cur;    
END
//