MySQL函数与存储过程字符串长度限制的解决
问题描述
MySQL函数或者存储过程中使用group_concat()函数导致数据字符过长而报错
BEGIN
declare ids varchar(1000) default ”;
declare tempids varchar(1000);
— 先根据标段号查询出数据组成临时表
DROP TEMPORARY TABLE IF EXISTS temp_weld_position;
CREATE TEMPORARY TABLE temp_weld_position AS
select t1.id,t1.section_num,t1.weld_code,t1.lon,t1.lat,t2.pipe1_num,t2.pipe2_num from
(select id,section_num,weld_code,lon,lat from weld_position where section_num = in_sectionNum and LENGTH(lon)>=7 and LENGTH(lat)>=6 and is_deleted=0) t1
join (select id,weld_code,pipe1_num,pipe2_num from weld_manage where section_num = in_sectionNum) t2 on t1.weld_code=t2.weld_code;
— 在根据传入的pipe2_num 递归查询出所有的数据,将pipe2_num当做id,pipe1_num当pid
set tempids = in_pipe2Num;
while tempids is not null do
set ids = CONCAT_WS(‘,’,ids,tempids);
select GROUP_CONCAT(pipe2_num) into tempids from temp_weld_position where FIND_IN_SET(pipe1_num,tempids)>0;
end while;
select t1.id,t1.section_num,t1.weld_code,t1.lon,t1.lat,t2.pipe1_num,t2.pipe2_num from
(select id,section_num,weld_code,lon,lat from weld_position where section_num = in_sectionNum and LENGTH(lon)>7 and LENGTH(lat)>6 and is_deleted=0) t1
join (select id,weld_code,pipe1_num,pipe2_num from weld_manage where section_num = in_sectionNum) t2 on t1.weld_code=t2.weld_code
where FIND_IN_SET(t2.pipe2_num,ids)
order by FIND_IN_SET(t2.pipe2_num,ids);
END
原因分析:
两个参数ids、tempids定义的varchar(1000),后续执行多次循环,GROUP_CONCAT拼接字符放入这两个参数时就会报字符串长度超限错误,因函数、存储过程中varchar类型最大长度为16383
解决方案:
将varchar(1000)类型变成text或者是BLOB类型解决此问题
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