When I execute
show columns from Employee
CREATE TABLE Employee (
id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
departmentId TINYINT UNSIGNED NOT NULL
COMMENT "CONSTRAINT FOREIGN KEY (departmentId) REFERENCES Department(id)",
firstName VARCHAR(20) NOT NULL,
lastName VARCHAR(40) NOT NULL,
email VARCHAR(60) NOT NULL,
ext SMALLINT UNSIGNED NULL,
hireDate TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
leaveDate DATETIME NULL,
INDEX name (lastName, firstName),
CREATE TABLE Department (
id TINYINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
MUL as opposed to
UNI means a non unique index and is shown for the first (or the only column) in an index when you issue a
SHOW COLUMNS command.
The only exception to this is
If more than one of the Key values applies to a given column of a table, Key displays the one with the highest priority, in the order PRI, UNI, MUL.
firstName is a second column in the composite index
name and therefore
MUL is not being displayed for it.
Further reading SHOW COLUMNS Syntax