Hello friends,
Today we learn how we can display the primary key of a table or database.

1. To display the primary key in a table we can execute any of the following command:

SHOW COLUMNS FROM <database_name>.<table_name> WHERE `Key` = "PRI";

SHOW { KEYS | INDEXES | INDEX } FROM <database_name>.<table_name> WHERE Key_name = 'PRIMARY';

SELECT k.column_name, t.table_name, t.table_schema, t.constraint_type FROM information_schema.table_constraints t JOIN information_schema.key_column_usage k USING ( constraint_name, table_schema, table_name ) WHERE t.constraint_type = 'PRIMARY KEY' AND t.table_schema = '<database_name>' AND t.table_name='<table_name>';

2. To display the primary key of a database we need to execute the following command:

SELECT k.column_name, t.table_name, t.table_schema, t.constraint_type
FROM information_schema.table_constraints t
JOIN information_schema.key_column_usage k
USING ( constraint_name, table_schema, table_name )
WHERE t.constraint_type = 'PRIMARY KEY'
AND t.table_schema = '<database_name>'

In all above MySQL statement in place of <database_name> we will write our database name and in place of <table_name> will write our table name.