因此，简而言之，这应该很简单...我有一个静态查询，我试图动态地重新创建它，但是它始终会产生语法错误。令人困惑的是，如果我复制粘贴select @statement输出，它将在MYSQL Workbench中正常运行。
下面，我将过程分为2个独立的execute语句，其中第二个看起来似乎是引起错误的原因，但是我认为这可能会引起误解（我将在下面解释原因）。
CREATE DEFINER=`admin`@`%` PROCEDURE `sp_calc_place_win_per`(
IN var_event_type_id int,
IN var_country varchar(45),
IN var_max_bsp float,
IN var_market_type varchar(45),
IN var_increment float,
IN var_first_increment float
)
BEGIN
drop temporary table if exists tbl_results;
if var_market_type = 'win' then
set @market_type = var_market_type;
set @rank = 1;
set @number_of_winners = 1;
else
set @market_type = var_market_type;
set @rank = 2;
set @number_of_winners = 2;
end if;
-- set @a = 'create temporary table tbl_results';
set @b = concat('create temporary table tbl_results select count(case when bsp between 0 and ', var_first_increment, ' then bsp end) as `0-', convert(var_first_increment,char),'` ');
set @statement = @b; -- concat(@a, @b);
set @start_range = round(var_first_increment + 0.01,2);
REPEAT
set @end_range = round(round(@start_range + var_increment - 0.01,2),2);
if @end_range > var_max_bsp - var_increment then
set @end_range = var_max_bsp;
end if;
set @c = concat(', count(case when bsp between ', round(@start_range,2),' and ', round(@end_range,2), ' then bsp end) as `',convert(@start_range,char),'-', convert(round(@end_range,2),char), '` ');
set @statement = concat(@statement,@c);
set @start_range = round(@end_range + 0.01,2);
UNTIL @end_range = var_max_bsp
END REPEAT;
set @d = concat(', count(case when bsp > ', round(@end_range,2), ' then bsp end) as `>', convert(round(@end_range,2),char), '` ');
set @e = concat(', winner FROM tbl_betfair_historic_data where event_id in (select event_id from tbl_betfair_historic_data where rank <=', @rank, ' and market_type ="', @market_type , '" and number_of_winners = ' , @number_of_winners, ' and bsp <=' , var_max_bsp , ' and country_code = "', var_country, '" and event_type_id = ', var_event_type_id, ' group by event_id) group by event_id, winner; ');
set @statement = concat(@statement, @d, @e);
prepare st1 from @statement;
execute st1;
-- This is purely in to test the first section produces the results as expected
select * from tbl_results;
-- This section dynamically creates n variables, depending on the var_max_bsp and var_increment variables
set @bsp = 0;
set @total_count = 0;
set @statement = concat(' set @total_', @total_count, ' = (select sum(b.`', @bsp, '-' , var_first_increment,'`) from tbl_results b);');
set @start_range = var_first_increment + 0.01;
REPEAT
set @total_count = @total_count + 1;
set @end_range = @start_range + var_increment - 0.01;
if @end_range > var_max_bsp - var_increment then
set @end_range = var_max_bsp;
end if;
set @s= concat(' set @total_', convert(@total_count,char), ' = (select sum(b.`', convert(round(@start_range,2),char), '-' , convert(round(@end_range,2),char),'`) from tbl_results b);');
set @statement = concat(@statement, @s);
set @start_range = @end_range + 0.01;
UNTIL @end_range = var_max_bsp
END REPEAT;
set @final_total = concat(' set @total_', convert(@total_count+1,char), ' = (select sum(b.`>', convert(round(@end_range,2),char),'`) from tbl_results b); ');
set @statement = concat(@statement, @final_total);
select @statement;
prepare st1 from @statement;
execute st1;
-- This is what the dynamic query should create
/*
set @total_0 = (select
sum(a.`0-1.4`)
from tbl_results a);
set @total_141 = (select
sum(a.`1.41-1.6`)
from tbl_results a);
set @total_161 = (select
sum(a.`1.61-1.83`)
from tbl_results a);
set @total_183 = (select
sum(a.`>1.83`)
from tbl_results a);
--This would then be the final section, below is the hard-coded version
select
sum(a.`0-1.4`)/@total_0 as '0-1.4',
sum(a.`1.41-1.6`)/@total_141 as '1.41-1.6',
sum(a.`1.61-1.83`)/@total_161 as '1.61-1.83',
sum(a.`>1.83`)/@total_183 as '>1.83',
if (winner=1,'winner','loser') as 'winner'
from tbl_results a
group by winner;
*/
drop temporary table if exists tbl_results;
END
如果我运行该代码，它将创建临时表tbl_results，因此第一部分确实可以正常工作，但随后我得到：
14:36:31 call sp_calc_place_win_per(4339, 'GB', 1.83, 'place', 0.2, 1.4) Error Code: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'set @total_1 = (select sum(b.`1.41-1.60`) from tbl_results b); set @total_2 = (s' at line 1
但是，如果我将过去的代码复制到Workbench中，则可以正常工作。
如果我连接两个@语句并作为一个语句运行，则这是它生成的SQL（产生相同的错误）：
'create temporary table tbl_results select count(case when bsp between 0 and 1.4 then bsp end) as `0-1.4` , count(case when bsp between 1.41 and 1.60 then bsp end) as `1.41-1.60` , count(case when bsp between 1.61 and 1.83 then bsp end) as `1.61-1.83` , count(case when bsp > 1.83 then bsp end) as `>1.83` , winner FROM tbl_betfair_historic_data where event_id in (select event_id from tbl_betfair_historic_data where rank <=2 and market_type =\"place\" and number_of_winners = 2 and bsp <=1.83 and country_code = \"GB\" and event_type_id = 4339 group by event_id) group by event_id, winner; set @total_0 = (select sum(b.`0-1.4`) from tbl_results b); set @total_1 = (select sum(b.`1.41-1.60`) from tbl_results b); set @total_2 = (select sum(b.`1.61-1.83`) from tbl_results b); set @total_3 = (select sum(b.`>1.83`) from tbl_results b); '
所以我确实想知道字符串是否可能引起了问题（例如country_code =和market_type =），因为“ GB”显然无法在MYSQL工作台中使用，但是如果我重新格式化这些字符串，整个事情就可以了（仅在Workbench中）。
我尝试过各种方法来重新格式化字符串，但是没有运气，但是我也不能100％确信这是问题所在，因为我可以验证我是否保留代码的原样（即使用2 x @statement）正在执行），然后从tbl_results中的select *中可以验证它确实创建了该表）。
希望这是足够的信息，但是如果某些部分没有意义，请告诉我，我将尝试扩展。
我完全被困在这里，因此不胜感激（感谢您，没有换行符，这是很抱歉的，这是因为有关该主题的先前类似问题建议换行符可能导致动态MYSQL存储过程出现问题）！
[UPDATE]，我们现在可以确定问题出在我代码的“第2部分”，我为第一部分创建了一个单独的过程，但是还包括了一个虚拟临时表的创建，因此它可能人们更容易复制我看到的错误：
CREATE DEFINER=`admin`@`%` PROCEDURE `sp_calc_place_win_per`(
IN var_event_type_id int,
IN var_country varchar(45),
IN var_max_bsp float,
IN var_market_type varchar(45),
IN var_increment float,
IN var_first_increment float
)
BEGIN
drop temporary table if exists tbl_results;
set @event_type_id = var_event_type_id;
set @country = var_country;
set @max_bsp = var_max_bsp;
set @market_type = var_market_type;
set @increment = var_increment;
set @first_increment = var_first_increment;
/*
prepare create_results_table from 'CALL sp_create_results_table(?,?,?,?,?,?)';
execute create_results_table using
@event_type_id, @country, @max_bsp,
@market_type, @increment, @first_increment;*/
-- Create Dummy tbl_results for testing
create temporary table tbl_results
(`0-1.40` float NOT NULL,
`1.41-1.60` float NOT NULL,
`1.61-1.83` float NOT NULL,
`>1.83` float NOT NULL
);
INSERT INTO tbl_results
(`0-1.40`,
`1.41-1.60`,
`1.61-1.83`,
`>1.83`)
VALUES (7, 5, 3, 2);
set @bsp = 0;
set @total_count = 0;
set @statement = concat(' select sum(tbl_results.`', @bsp, '-' , var_first_increment,'`) into @total_', @total_count,
' from tbl_results;');
set @start_range = var_first_increment + 0.01;
REPEAT
set @total_count = @total_count + 1;
set @end_range = @start_range + var_increment - 0.01;
if @end_range > var_max_bsp - var_increment then
set @end_range = var_max_bsp;
end if;
set @s= concat(' select sum(tbl_results.`', convert(round(@start_range,2),char), '-' ,
convert(round(@end_range,2),char),'`) into @total_', convert(@total_count,char), ' from tbl_results;');
set @statement = concat(@statement, @s);
set @start_range = @end_range + 0.01;
UNTIL @end_range = var_max_bsp
END REPEAT;
set @final_total = concat(' select sum(tbl_results.`>', convert(round(@end_range,2),char),'`) into @total_',
convert(@total_count+1,char), ' from tbl_results; ');
set @statement = concat(@statement, ' ', @final_total);
SELECT @statement;
prepare st1 from @statement;
execute st1;
/*
set @total_0 = (select
sum(a.`0-1.4`)
from tbl_results a);
set @total_141 = (select
sum(a.`1.41-1.6`)
from tbl_results a);
set @total_161 = (select
sum(a.`1.61-1.83`)
from tbl_results a);
set @total_183 = (select
sum(a.`>1.83`)
from tbl_results a);
select
sum(a.`0-1.4`)/@total_0 as '0-1.4',
sum(a.`1.41-1.6`)/@total_141 as '1.41-1.6',
sum(a.`1.61-1.83`)/@total_161 as '1.61-1.83',
sum(a.`>1.83`)/@total_183 as '>1.83',
if (winner=1,'winner','loser') as 'winner'
from tbl_results a
group by winner;
select @statement;
*/
drop temporary table if exists tbl_results;