使用 concat 處理 MySQL

Question

你能幫我嗎？

BEGIN

set @currentdate=now();

set @formateddate=convert(date_format(@currentdate,'%Y%m%d'),char);

select @t;

drop table if exists CONCAT('account_class_',@formateddate) 

,CONCAT('class_courses_',@formateddate),CONCAT('student_',@formateddate),CONCAT(

'messages_',@formateddate),CONCAT('announcement_',@formateddate),CONCAT('student

_activity_',@formateddate),CONCAT('activity_',@formateddate),CONCAT('account_cla

ss_students_',@formateddate);

create table CONCAT('account_class_',@formateddate) select * from account_class;

create table CONCAT('class_courses_',@formateddate) select * from class_courses;

create table CONCAT('student_',@formateddate) select * from student;

create table CONCAT('messages_',@formateddate) select * from messages;

create table CONCAT('announcement_',@formateddate) select * from announcement;

create table CONCAT('student_activity_',@formateddate) select * from 

student_activity;

create table CONCAT('activity_',@formateddate) select * from activity;

create table CONCAT('account_class_students_',@formateddate) select * from 

account_class_students;


END

問題是什么？

Answer 1

您正在嘗試構造一個表名。 這是不允許的。 理論上，您可以使用動態 SQL：

declare @sql;

set @sql = replace('create table [table] select * from account_class',
                   [table], 'CONCAT('account_class_', @formateddate));

prepare x from @sql;

execute x;

但是，我不鼓勵創建如此大量的表，因為簡單的視圖可以執行您想要的操作（或只是一個where子句）。