mysql - Error on SQL Server tables while performing a join -

i'm trying perform join between 4 tables schedule table, employee table, machine table , plate table.

problem is, @ schedule table primary key date while on rest of table have primary key char. i'm trying convert primary key in table char make same 1 on others don't know how. here have done far

create table machine (     machineid char(5),     machinetype varchar(10) not null,     machinestatus varchar(10)not null )  create table employee (     employeeid char(5) primary key,     employeename varchar(30) not null, )  create table plate (     plateid char(5) primary key,     platemodel varchar(30) not null, )  create table machineschedule (     dateschedule date primary key, ) 

here join

select employee.employename, plate.platemodel, machine.machineid, machine.machinetype, machine.machinestatus employee, plate, machine join machineschedule on machineschedule.dateschedule=machine.machineid; 

and here error gave conversion failed when converting date and/or time character string.

your table structure incorrect, should use integer datatype primary key not char or datetime creates indexing , can not join table on char , date datatype never have same value; , lastly join other tables in clause. there should join condition employee, plate, machine.

and primary , foreign key constraints missing