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sky scraper
sky scraper

Reputation: 2214

SQL query to find Primary Key of a table?

How can I find which column is the primary key of a table by using a query?

Upvotes: 27

Views: 180848

Answers (12)

Atharullah
Atharullah

Reputation: 5

For SQL Server

select Column_Name from information_schema.key_column_usage
where 
Constraint_Catalog='**DB_Name**' and
Constraint_Schema='**Schema Name**' and
Table_Name='**Table Name**' and
constraint_name like 'PK%'

Upvotes: 0

Shareef DotNet Guru
Shareef DotNet Guru

Reputation: 49

For MS SQL Sever easy way to get the Primary key for the table

EXEC sp_pkeys TableName;

ex: EXEC sp_pkeys Users;

Upvotes: 0

Peter Lionhart
Peter Lionhart

Reputation: 31

LEFT joining table_constraints seems to take more time on mine. i use Information_schema.COLUMNS

SELECT TABLE_SCHEMA , TABLE_NAME , COLUMN_NAME 
FROM Information_schema.Columns 
WHERE COLUMN_KEY = "PRI" AND TABLE_SCHEMA = DATABASE()

Upvotes: 0

Razel Marquez Bigayan
Razel Marquez Bigayan

Reputation: 45

This this on SSMS -----

SELECT TABLE_CATALOG, TABLE_NAME, COLUMN_NAME
FROM INFORMATION_SCHEMA.key_column_usage
WHERE TABLE_NAME='YOUR_TABLE'------

Upvotes: 0

Maksim Yurchak
Maksim Yurchak

Reputation: 21

It's more easy way to do it:

DESC TABLE;

It shows you the structure of your TABLE;

Upvotes: 1

Ashish Thombre
Ashish Thombre

Reputation: 11

For MSSQL: SELECT DISTINCT C.TABLE_NAME,C.COLUMN_NAME,C.DATA_TYPE FROM sys.indexes I INNER JOIN sys.index_columns IC ON I.OBJECT_ID = IC.OBJECT_ID AND I.INDEX_ID = IC.INDEX_ID INNER JOIN information_schema.columns C ON COL_NAME(IC.OBJECT_ID,IC.COLUMN_ID) = C.COLUMN_NAME WHERE I.IS_PRIMARY_KEY = 1

Upvotes: -1

Brian Wangombe
Brian Wangombe

Reputation: 39

In mySQL 

SHOW COLUMNS FROM `table_name`;

This show the details of the columns ie field, data-type, key etc.

Upvotes: 3

João Silva
João Silva

Reputation: 91369

For Oracle, you can look it up in the ALL_CONSTRAINTS table:

SELECT a.COLUMN_NAME
FROM all_cons_columns a INNER JOIN all_constraints c 
     ON a.constraint_name = c.constraint_name 
WHERE c.table_name = 'TBL'
  AND c.constraint_type = 'P';

DEMO.

For SQL Server, it was already answered here, and for MySQL check @ajon's answer.

Upvotes: 16

Romuald Brunet
Romuald Brunet

Reputation: 5839

For MySQL:

SELECT GROUP_CONCAT(COLUMN_NAME), TABLE_NAME
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE
  TABLE_SCHEMA = '**database name**'
  AND CONSTRAINT_NAME='PRIMARY'
GROUP BY TABLE_NAME;

Warning a primary key with two columns will have them separated by a coma (,)

Upvotes: 12

BhandariS
BhandariS

Reputation: 604

The following query gives the list of all the primary keys in the given database.

SELECT DISTINCT TABLE_NAME ,column_name
    FROM INFORMATION_SCHEMA.key_column_usage
    WHERE TABLE_SCHEMA IN ('*your_db_name*');

Upvotes: 3

user1577417
user1577417

Reputation: 126

Try this query in SQL server:

SELECT     X.NAME AS INDEXNAME,
           COL_NAME(IC.OBJECT_ID,IC.COLUMN_ID) AS COLUMNNAME
FROM       SYS.INDEXES  X 
INNER JOIN SYS.INDEX_COLUMNS  IC 
        ON X.OBJECT_ID = IC.OBJECT_ID
       AND X.INDEX_ID = IC.INDEX_ID
WHERE      X.IS_PRIMARY_KEY = 1
  AND      OBJECT_NAME(IC.OBJECT_ID)='YOUR_TABLE'

Upvotes: 7

alanmanderson
alanmanderson

Reputation: 8230

This is a duplicate question:

credit to Lukmdo for this answer:

It might be not advised but works just fine:

show index from TABLE where Key_name = 'PRIMARY' ;

The solid way is to use information_schema:

SELECT k.COLUMN_NAME
FROM information_schema.table_constraints t
LEFT 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()
    AND t.table_name='owalog';

Upvotes: 28

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