mysql使用Execute和直接执行select语句结果不相同！

[Diana_24]

mysql中使用execute语句如下
prepare stmt from 'select sum(cig_cnt) from cigstrinf where cig_type = ''红南京''';
execute stmt;
结果为 null;
而直接执行select sum(cig_cnt) from cigstrinf where cig_type = '红南京';
能够得到正确的结果22
不明白为什么会出现如此的情况，请赐教！

[Diana_24]

将两句话写入存储过程，调用存储过程之后的结果为：
sum(cig_amount)
22
sum(cig_amount)
NULL
我觉得可能是字符集的问题，但是两种查询方式都用了汉字，为什么结果还会不一样呢？
show variables like '%character_set%'结果为：
client gbk
connection gbk
database gbk
filesystem gbk
results gbk
server gbk
system utf8

表中cig_amount字段的Collation设置为NULL
cig_type字段的Collation设置为gbk_chinese_ci

[wwwwb]

SET NAMES GBK
再运行试试

[ACMAIN_CHM]

你表的这个字段的字符集设置是什么？

[wwwwb]

prepare stmt from 'select sum(cig_cnt) from cigstrinf where cig_type = "红南京"';
execute stmt;

or

PREPARE stmt FROM 'select sum(cig_cnt) from cigstrinf where cig_type =\'红南京\'';
EXECUTE stmt;

[rucypli]

可能是字符集的问题

两句话都放到存储过程里面一起执行看看
select sum(cig_cnt) from cigstrinf where cig_type = '红南京';
prepare stmt from 'select sum(cig_cnt) from cigstrinf where cig_type = ''红南京''';
execute stmt;

[wwwwb]

show variables like 'char%';

[nicenight]

这个 where 条件最后匹配的结果为空，

prepare stmt from 'select sum(cig_cnt) from cigstrinf where cig_type = ''红南京''';

改成如下试试：

prepare stmt from 'select sum(cig_cnt) from cigstrinf where cig_type = "红南京"';

或

prepare stmt from "select sum(cig_cnt) from cigstrinf where cig_type = '红南京'";

[Rotel-刘志东]

set @sql='select sum(cig_cnt) from cigstrinf where cig_type = ''红南京''''
prepare stmt from @sql;
execute stmt;

[Rotel-刘志东]

表中字符集是怎样的。
show variables like '%char%';

[Diana_24]

set names gbk不就是把几个参数设置为gbk吗，我的那几个字符集设计已经是gbk格式啦

[Diana_24]

都没人搭理我的。。。