MySQL存储过程在动态sql内获取返回值

MySQL动态SQL与存储过程

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本文介绍MySQL中如何通过存储过程实现动态SQL的构建与执行，包括查询总记录数、分页查询等实用技巧，并提供了具体的示例代码。

MySQL存储过程在动态sql内获取返回值

2012-05-04 18:21:32| 分类： MySQL | 标签：mysql procedure |字号订阅

不需要使用游标循环来读取，直接select * into @变量就OK了，还可以传递参数来执行。 
1MySql通用分页存储过程
 2
 3过程参数
 4p_cloumns varchar(500),p_tables varchar(100),p_where varchar(4000),p_order varchar(100),p_pageindex int,p_pagesize int,out p_recordcount int,out p_pagecount int
 5
 6$$:begin
 7    declare v_sqlcounts varchar(4000);
 8    declare v_sqlselect varchar(4000);
 9    #拼接查询总记录的SQL语句
10    set v_sqlcounts = concat('select count(*) into @recordcount from ',p_tables,p_where);
11    #select v_sqlcounts;leave $$;
12    set @sqlcounts = v_sqlcounts;
13    prepare stmt from @sqlcounts;
14         execute stmt;
15    deallocate prepare stmt;
16    #获取动态SQL语句返回值
17    set p_recordcount = @recordcount;
18    #根据总记录跳数计算出总页数
19    set p_pagecount = ceiling((p_recordcount+0.0)/p_pagesize);
20    if p_pageindex <1 then
21        set p_pageindex = 1;
22    elseif p_pageindex > p_pagecount and p_pagecount <> 0 then
23        set p_pageindex = p_pagecount;
24    end if;
25    #拼接分页查询记录的动态SQL语句
26    set v_sqlselect = concat('select ',p_cloumns,' from ',p_tables,p_where,if(p_order is not null,p_order,''),' limit ',(p_pageindex-1)*p_pagesize,' , ',p_pagesize);
27    #select v_sqlselect;leave $$;
28    set @sqlselect = v_sqlselect;
29    prepare stmtselect from @sqlselect;
30    execute stmtselect;
31    deallocate prepare stmtselect;
32end $$

Sql代码
#拼接查询总记录的SQL语句 
set v_sqlcounts = concat('select count(*) into @recordcount from ',v_tables,v_where); 
set @sqlcounts := v_sqlcounts; 
#预处理动态SQL 
prepare stmt from @sqlcounts; 
#传递动态SQL内参数 
set @s1= categoryid; 
execute stmt using @s1; 
deallocate prepare stmt; 
#获取动态SQL语句返回值 
set recordcount = @recordcount; 
#拼接查询总记录的SQL语句 set v_sqlcounts = concat('select count(*) into @recordcount from ',v_tables,v_where); set @sqlcounts := v_sqlcounts; #预处理动态SQL prepare stmt from @sqlcounts; #传递动态SQL内参数 set @s1= categoryid; execute stmt using @s1; deallocate prepare stmt; #获取动态SQL语句返回值 set recordcount = @recordcount;

引用：http://apps.hi.baidu.com/share/detail/5447167

例子：

传入表明和参数及列明拼成sql执行：

DELIMITER $$
CREATE PROCEDURE set_col_value
(in_table VARCHAR(128),in_column VARCHAR(128),in_new_value VARCHAR(1000),in_where VARCHAR(4000))
begin

DECLARE l_sql VARCHAR(4000);
SET l_sql=CONCAT('',' UPDATE ',in_table,' SET ',in_column,'=',in_new_value,' WHERE ',in_where);
SET @sql=l_sql;
PREPARE s1 FROM @sql;
EXECUTE s1;
DEALLOCATE PREPARE s1;
end$$

DELIMITER ;