#1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key

Question

I have a serial no. column which is auto increment, but I want enrollment id. to be the primary key and MySQL is just not allowing me to do that. Is there any way around to do that?

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Answer 1

You can only define a column as AUTO_INCREMENT if it is a PRIMARY KEY and an INT ^{( not sure of this but BIGINT will work too )} . Since you want the SerialNo to be set as AUTO_INCREMENT , why not make it as PRIMARY KEY and the EnrollmentID as UNIQUE ?

CREATE TABLE TableName
(
    SerialNo INT AUTO_INCREMENT PRIMARY KEY,
    EnrollmentID INT UNIQUE,
    -- other columns...
)

Answer 2

确保将序列号列定义为UNIQUE 。

Answer 3

CREATE TABLE tbl_login<\/code> ( id<\/code> int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY , first_name<\/code> varchar(100) NOT NULL, last_name<\/code> varchar(100) NOT NULL, gender<\/code> varchar(30) NOT NULL, email<\/code> varchar(200) NOT NULL, password<\/code> varchar( 200) 非空， address<\/code>文本非空， mobile_no<\/code> varchar(15) 非空) ENGINE=InnoDB DEFAULT CHARSET=latin1;

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