Question

我正在尝试创建一个允许我输入表名作为变量（tblname）的过程，然后对该表执行一些操作。我在函数中引用的callingparty和callduration列是将要使用的任何表的预先存在的列。我是创建程序的新手，每次修复错误时都会弹出另一个程序。

目前我收到错误：

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'concat(short, tblname); create temporary table temp (index callingparty (calling' at line 8

我不知道如何解决这个或我的语法有什么问题。是否只能创建一个包含旧表名称的新表？

drop procedure if exists shortcallcount;

delimiter $$
create procedure shortcallcount(`tblname` varchar(32))

begin
drop table if exists temp;
drop table if exists temp2;
drop table if exists temp3;
drop table if exists join1;
drop table if exists concat(short, tblname);
create temporary table temp (index callingparty (callingparty)) as select callingparty, count(*) as totalcount from tblname group by callingparty;
create temporary table temp2 (index callingparty (callingparty)) as select callingparty, count(*) as tencount from tblname where callduration<1000 group by callingparty;
create temporary table temp3 (index callingparty (callingparty)) as select callingparty, count(*) as fourcount from tblname where callduration<492 group by callingparty;

create temporary table join1 (index callingparty (callingparty)) as select temp.callingparty, ifnull(temp3.fourcount, 0) as fourcount, temp.totalcount from temp left outer join temp3 on temp.callingparty=temp3.callingparty;
create table concat(short, tblname) (index callingparty (callingparty)) as select join1.callingparty, join1.fourcount; ifnull(temp2.tencount, 0) as tencount, join1.totalcount from join1 left outer join temp2 on join1.callingparty=temp2.callingparty;
drop table temp;
drop table temp2;
drop table temp3;
drop table join1;
end$$

delimiter ;

Answer 1

您可以使用预准备语句，因为变量名称不会对表名或列名进行评估。

delimiter $$
create procedure shortcallcount(tblname varchar(32))
begin
    drop table if exists temp;
    drop table if exists temp2;
    drop table if exists temp3;
    drop table if exists join1;
    -- drop table if exists concat(short, tblname);
    set @sql = concat("drop table if exists short", tblname,";");
    PREPARE stmt1 FROM @sql;
    EXECUTE stmt1;
    DEALLOCATE PREPARE stmt1;

    create temporary table temp (index callingparty (callingparty)) as select callingparty, count(*) as totalcount from tblname group by callingparty;
    create temporary table temp2 (index callingparty (callingparty)) as select callingparty, count(*) as tencount from tblname where callduration<1000 group by callingparty;
    create temporary table temp3 (index callingparty (callingparty)) as select callingparty, count(*) as fourcount from tblname where callduration<492 group by callingparty;

    create temporary table join1 (index callingparty (callingparty)) as select temp.callingparty, ifnull(temp3.fourcount, 0) as fourcount, temp.totalcount from temp left outer join temp3 on temp.callingparty=temp3.callingparty;
    -- create table concat(short, tblname) (index callingparty (callingparty)) as select join1.callingparty, join1.fourcount; ifnull(temp2.tencount, 0) as tencount, join1.totalcount from join1 left outer join temp2 on join1.callingparty=temp2.callingparty;
    set @sql = concat("create table short",tblname," (index callingparty (callingparty)) as select join1.callingparty, join1.fourcount; ifnull(temp2.tencount, 0) as tencount, join1.totalcount from join1 left outer join temp2 on join1.callingparty=temp2.callingparty;");
    PREPARE stmt2 FROM @sql;
    EXECUTE stmt2;
    DEALLOCATE PREPARE stmt2;

    drop table temp;
    drop table temp2;
    drop table temp3;
    drop table join1;
end$$

delimiter ;

在MySQL中创建用户定义的过程

1 个答案: