Show tables, describe tables equivalent in redshift

Question

I'm new to aws, can anyone tell me what are redshifts' equivalents to mysql commands?

show tables -- redshift command
describe table_name -- redshift command

Astereognosis

Answer 1

All the information can be found in a PG_TABLE_DEF table, documentation.

Listing all tables in a public schema (default) - show tables equivalent:

SELECT DISTINCT tablename
FROM pg_table_def
WHERE schemaname = 'public'
ORDER BY tablename;

Description of all the columns from a table called table_name - describe table equivalent:

SELECT *
FROM pg_table_def
WHERE tablename = 'table_name'
AND schemaname = 'public';

---

Update:

As pointed by @Kishan Pandey 's answer, if you are looking for details of a schema different by public, you need to set search_path to my_schema. (show search_path display current search path)

Listing tables in my_schema schema:

set search_path to my_schema;
select * from pg_table_def;

Keelboat

Is there way to fetch default values set of respective columns ? – Vie

pg_table_def returns index also. safer to use select distinct table_name from information_schema.columns where table_schema = 'public' instead. – Elvieelvin

is that in column order ? – Gird

see alberton.info/postgresql_meta_info.html for a bunch of simpler ways to extract column info, including order – Gird

Maybe they used work to at the time of this answer, but these queries don't return all tables anymore (2018-07-11). For example, I created my own schema and created a table in that schema, and the pg_table_def table doesn't have any information about that table. The query suggested by @Elvieelvin -- to query information_schema instead does work. – Hardigg

as pointed by @Kishan Pandey 's answer, if you are looking for details of a schema different by public, you need to set search_path to my_schema and consequently update the query to filter on schemaname = 'my_schema' – Combinative

This did not show some tables that \d+ <table name> below did. – Damascene

what about temp tables? I want to describe a temp table I created but temp tables cant be created with schema – Methinks

Answer 2

I had to select from the information schema to get details of my tables and columns; in case it helps anyone:

SELECT * FROM information_schema.tables
WHERE table_schema = 'myschema'; 

SELECT * FROM information_schema.columns
WHERE table_schema = 'myschema' AND table_name = 'mytable'; 

Cantone

I am storing all our Segment SQL data to AWS Redshift, and so far this is the only solution I have come across that has worked for me! – Microelement

I find this the superior method. The information_schema in Redshift is a superset of pg_table. Furthermore, pg_table_def seems to suffer from some kind of permission issue: while a schema/table will be in pg_tables, the corresponding information in pg_table_def will NOT be there. All I get is pg_catalog and public schemae. Frustrating. – Finke

@MarkGerolimatos To see your tables in pg_table_def, you must add the schema to your SEARCH_PATH: SET SEARCH_PATH to '$user', public, YOUR_SCEHMA_NAME. Definitely not intuitive... – Scutt

@MarcoRoy Worth mentiong that, the pg_table_def is more informative as I see from the query results. pg_table_def shows whether the column is distkey or sortkey and its encoding, which are not shown in the information_schema.columns. I guess that's where SQL clients like DataGrip gets the DDL from. – Pinnule

Answer 3

Or simply:

\dt to show tables

\d+ <table name> to describe a table

Edit: Works using the psql command line client

Merlynmermaid

This does not work for me .. it would work in Posgres but not Redshift .. better to go with Tomasz' answer. – Demilitarize

I am accessing Redshift via SQLWorkbench (as recommended in the AWS getting started guide). If I try \dt I get Error: Syntax error at or near "\". Are you accessing Redshift in some other way? – Demilitarize

Yes, using psql command line client. I will update my answer. – Merlynmermaid

Actually I didn't realise you could connect to Redshift with the psql client, but it is in the Amazon documentation. It's actually very useful. Thanks. – Demilitarize

It shows slightly different information than Tomasz's solution. For example, \d+ tablename does not show sortkey information. – Nardoo

Answer 4

Tomasz Tybulewicz answer is good way to go.

SELECT * FROM pg_table_def WHERE tablename = 'YOUR_TABLE_NAME' AND schemaname = 'YOUR_SCHEMA_NAME';

If schema name is not defined in search path , that query will show empty result. Please first check search path by below code.

SHOW SEARCH_PATH

If schema name is not defined in search path , you can reset search path.

SET SEARCH_PATH to '$user', public, YOUR_SCEHMA_NAME

Licking

You may want to add the search path comment to Tomasz's answer. I had this issue the first time I used the pg views and had to research it. – Orten

This is the correct solution concerned with SEARCH_PATH. But I only need to set search_path to my_schema_name. – Pinnule

Answer 5

Redshift provides system tables and views which are simpler to use than the postgres default pg_catalog and information_schema tables. You can find the list of tables here

To get list of tables in a schema, you can query SVV_ALL_TABLES / SVV_REDSHIFT_TABLES

    select * from SVV_REDSHIFT_TABLES where schema_name = '<<schema_name>>';

To get table definition including is sort key and distribution key, you can query SVV_REDSHIFT_COLUMNS

    select * from SVV_REDSHIFT_COLUMNS where schema_name = '<<schema_name>>' and table_name = '<<table_name>>';

Ironmaster

Answer 6

You can use - desc / to see the view/table definition in Redshift. I have been using Workbench/J as a SQL client for Redshift and it gives the definition in the Messages tab adjacent to Result tab.

Agrarian

thanks for that! Still missing a way of listing tables :/ – Drier

Answer 7

In the following post, I documented queries to retrieve TABLE and COLUMN comments from Redshift. https://sqlsylvia.wordpress.com/2017/04/29/redshift-comment-views-documenting-data/

Enjoy!

Table Comments

    SELECT n.nspname AS schema_name
     , pg_get_userbyid(c.relowner) AS table_owner
     , c.relname AS table_name
     , CASE WHEN c.relkind = 'v' THEN 'view' ELSE 'table' END 
       AS table_type
     , d.description AS table_description
     FROM pg_class As c
     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
     LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
     LEFT JOIN pg_description As d 
          ON (d.objoid = c.oid AND d.objsubid = 0)
     WHERE c.relkind IN('r', 'v') AND d.description > ''
     ORDER BY n.nspname, c.relname ;

Column Comments

    SELECT n.nspname AS schema_name
     , pg_get_userbyid(c.relowner) AS table_owner
     , c.relname AS table_name
     , a.attname AS column_name
     , d.description AS column_description
    FROM pg_class AS c
    INNER JOIN pg_attribute As a ON c.oid = a.attrelid
    INNER JOIN pg_namespace n ON n.oid = c.relnamespace
    LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
    LEFT JOIN pg_description As d 
     ON (d.objoid = c.oid AND d.objsubid = a.attnum)
    WHERE c.relkind IN('r', 'v')
     AND a.attname NOT         
     IN ('cmax', 'oid', 'cmin', 'deletexid', 'ctid', 'tableoid','xmax', 'xmin', 'insertxid')
    ORDER BY n.nspname, c.relname, a.attname;

Intrigue

Answer 8

Shortcut

\d for show all tables

\d tablename to describe table

\? for more shortcuts for redshift

Manlove

Answer 9

redshift now support show table

show table analytics.dw_users

https://forums.aws.amazon.com/ann.jspa?annID=8641

Cotenant

Answer 10

You can simply use the command below to describe a table.

desc table-name

or

desc schema-name.table-name

Gilliam