Sql – How to get column names from a table in Oracle

databaseoraclesql

I need to query the database to get the column names, not to be confused with data in the table. For example, if I have a table named EVENT_LOG that contains eventID, eventType, eventDesc, and eventTime, then I would want to retrieve those field names from the query and nothing else.

I found how to do this in:

But I need to know: how can this be done in Oracle?

Best Answer

You can query the USER_TAB_COLUMNS table for table column metadata.

SELECT table_name, column_name, data_type, data_length
FROM USER_TAB_COLUMNS
WHERE table_name = 'MYTABLE'

Related Solutions

Mysql – How to select the nth row in a SQL database table

There are ways of doing this in optional parts of the standard, but a lot of databases support their own way of doing it.

A really good site that talks about this and other things is http://troels.arvin.dk/db/rdbms/#select-limit.

Basically, PostgreSQL and MySQL supports the non-standard:

SELECT...
LIMIT y OFFSET x

Oracle, DB2 and MSSQL supports the standard windowing functions:

SELECT * FROM (
  SELECT
    ROW_NUMBER() OVER (ORDER BY key ASC) AS rownumber,
    columns
  FROM tablename
) AS foo
WHERE rownumber <= n

(which I just copied from the site linked above since I never use those DBs)

Update: As of PostgreSQL 8.4 the standard windowing functions are supported, so expect the second example to work for PostgreSQL as well.

Update: SQLite added window functions support in version 3.25.0 on 2018-09-15 so both forms also work in SQLite.

Sql – How to find duplicate values in a table in Oracle

Aggregate the column by COUNT, then use a HAVING clause to find values that appear greater than one time.

SELECT column_name, COUNT(column_name)
FROM table_name
GROUP BY column_name
HAVING COUNT(column_name) > 1;

Best Answer

Related Solutions

Mysql – How to select the nth row in a SQL database table

Sql – How to find duplicate values in a table in Oracle

Related Topic