Related
My Postgres database was migrated from MySQL using a tool and the code base has lot of syntax issues.
One of the issues is with the UPDATE statements inside procedures where the column name contains alias name as below.
UPDATE table1 t1 SET t1.col1 = 'some_value';
Having alias name after SET keyword as in t1.col1 is a wrong syntax in Postgres.
As the number of procedures is huge, I'm trying to write a regular expression to find which procedures have this pattern.
select proname, prosrc from pg_proc
where regexp_replace(prosrc, E'[\\n\\r]+', ' ', 'g' ) ~* '[:UPDATE:]([[:space:]]+)[:set:]([[:space:]]+)^[a-z]([a-z]|[0-9])+\.^[a-z]([a-z]|[0-9])+([[:space:]]*)[:=:]';
The regexp_replace part on the left side of the condition is to remove line breaks which works fine. The main part on the right side is not returning the desired result.
I am trying to find the procedures that has UPDATE keyword followed by one or more space, followed by SET keyword, followed by one more space, followed by one more alphanumeric characters (which starts with an alphabet), followed by a dot(.) , followed by one more alphanumeric characters (which starts with an alphabet), followed by zero or more spaces, followed by an equal to sign (=).
But the statement I formed seems to be wrong. Any help on this is much appreciated.
I think this may be more complex than you think... A procedure/function may have more than one update statement, and a simple regex will likely come up with many false positives.
I think you want a function to do a better job of eliminating false positives that result from:
Alias that occurs after the update, in a separate statement (after the semicolon) -- fix by splitting statements by semicolons
Aliases within the update that occur after a FROM or WHERE clause, which are valid and not syntax errors
Less frequent, aliases used in a CTE prior to the update - fix by ignoring everything prior to the update keyword
Here is a boilerplate for what I think will get you close and minimize false positives:
create or replace function find_bad_syntax()
returns setof text
language plpgsql as
$BODY$
DECLARE
r pg_proc%rowtype;
dml varchar[];
eval varchar;
alias varchar;
BEGIN
FOR r IN
SELECT * FROM pg_proc WHERE prosrc ilike '%update%'
LOOP
dml := string_to_array (r.prosrc, ';');
foreach eval in array dml
loop
alias := substring (lower (eval), 'update [\w.]+\s+(\w+)');
continue when alias is null or lower (alias) = 'set';
eval := regexp_replace (eval, 'from\s+.*', '', 'i');
eval := regexp_replace (eval, 'where\s.*', '', 'i');
eval := regexp_replace (eval, '^.*update', '', 'i');
if eval ~* (alias || '\.\w+\s*=') then
-- if eval ~* (alias || '\.\w+\s+=') then
return next format ('PROC: %s ALIAS: %s => ERROR: %s', r.proname, alias, eval);
end if;
end loop;
END LOOP;
END;
$BODY$
So to get the results simply:
select * from find_bad_syntax()
I did a test run, and your function did show up in the results.
The below query gives me the expected results. It checks for code where we have SET followed by one or more space, followed by one or more alphanumeric character and _, followed by a dot(.), followed by one or more alphanumeric character and _, followed by one or more spaces and followed by =.
This fetches all the procedures that have the issue that I posted in question.
select proname, prosrc from pg_proc
where regexp_replace(prosrc, E'[\\n\\r]+', ' ', 'g' )
~* '( SET)[[:space:]]+([a-z]|[0-9]|(_))+\.([a-z]|[0-9]|(_))+[[:space:]]+(=)';
Yes, in PostgreSQL this is not working:
UPDATE table1 t1 SET t1.col1 = 'some_value';
But, this is working correctly:
UPDATE table1 t1 SET col1 = 'some_value';
So we only need to clear the update field alias.
Example for do it:
with t1(txt) as (
select 'UPDATE table1 t1 SET t1.col1 = some_value'
)
select regexp_replace(t1.txt, 'SET (.*)\d\.', 'SET ', 'g') from t1
For finding, selecting:
with t1(txt) as (
select 'UPDATE table1 t1 SET t1.col1 = some_value'
)
select * from t1 where t1.txt ~ 'SET (.*)\d\.'
Some small changes:
with t1(txt) as (
select 'UPDATE table1 t1 SET t1.col1 = some_value'
union all
select 'UPDATE table1 tbp3232 SET tbp3232.col1 = some_value'
union all
select 'select pp3.* from table1 pp3'
union all
select 'UPDATE table1 SET col1 = some_value'
union all
select 'UPDATE table1 t SET t.col1 = some_value'
)
select * from t1 where t1.txt ~ 'SET (.*)\w\.'
--Result:
'UPDATE table1 t1 SET t1.col1 = some_value'
'UPDATE table1 tbp3232 SET tbp3232.col1 = some_value'
'UPDATE table1 t SET t.col1 = some_value'
I just wonder how to eval the content of dynamic SQL using one select; this is the example. This is only an example. but I would like dynamically functions, and manage using single selects. ( I know that sqls are only for SELECT instead of modify... but In this deep querentee Im becomeing in a crazy developer)
SELECT 'SELECT SETVAL(' || chr(39) || c.relname || chr(39)|| ' ,
(SELECT MAX(Id)+1 FROM ' || regexp_replace(c.relname, '_[a-zA-Z]+_[a-zA-Z]+(_[a-zA-Z0-9]+)?', '', 'g') ||' ), true );'
FROM pg_class c WHERE c.relkind = 'S';
The original output is:
SELECT SETVAL('viewitem_id_seq' , (SELECT MAX(Id)+1 FROM viewitem ), true );
SELECT SETVAL('userform_id_seq' , (SELECT MAX(Id)+1 FROM userform ), true );
This is the dynamic sentence:
(SELECT MAX(Id)+1 FROM ' || regexp_replace(c.relname, '[a-zA-Z]+[a-zA-Z]+(_[a-zA-Z0-9]+)?', '', 'g')
is an string that generates as output a SQL, how to eval in the same line this statement?
The desired output is:
SELECT SETVAL('viewitem_id_seq' , 25, true );
SELECT SETVAL('userform_id_seq' , 85, true );
thanks!
If those are serial or identity columns it would be better to use pg_get_serial_sequence() to get the link between a table's column and its sequence.
You can actually run dynamic SQL inside a SQL statement by using query_to_xml()
I use the following script if I need to synchronize the sequences for serial (or identity) columns with their actual values:
with sequences as (
-- this query is only to identify all sequences that belong to a column
-- it's essentially similar to your select * from pg_class where reltype = 'S'
-- but returns the sequence name, table and column name to which the
-- sequence belongs
select *
from (
select table_schema,
table_name,
column_name,
pg_get_serial_sequence(format('%I.%I', table_schema, table_name), column_name) as col_sequence
from information_schema.columns
where table_schema not in ('pg_catalog', 'information_schema')
) t
where col_sequence is not null
), maxvals as (
select table_schema, table_name, column_name, col_sequence,
--
-- this is the "magic" that runs the SELECT MAX() query
--
(xpath('/row/max/text()',
query_to_xml(format('select max(%I) from %I.%I', column_name, table_schema, table_name), true, true, ''))
)[1]::text::bigint as max_val
from sequences
)
select table_schema,
table_name,
column_name,
col_sequence,
coalesce(max_val, 0) as max_val,
setval(col_sequence, coalesce(max_val, 1)) --<< this uses the value from the dynamic query
from maxvals;
The dynamic part here is the call to query_to_xml()
First I use format() to properly deal with identifiers. It also makes writing the SQL easier as no concatenation is required. So for every table returned by the first CTE, something like this is executed:
query_to_xml('select max(id) from public.some_table', true, true, '')
This returns something like:
<row xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<max>42</max>
</row>
The value is than extracted from the XML value using xpath() and converted to a number which then is used in the final SELECT to actually call setval()
The nesting with multiple CTEs is only used to make each part more readable.
The same approach can e.g. used to find the row count for all tables
Some background on how query_to_xml() works
I am trying to JOIN 2 queries in DQL but I am getting an error which says,
[Semantical Error] line 0, col 114 near '(select u.email': Error: Class '(' is not defined.
I have gone through https://stackoverflow.com/questions/24600439/error-in-nested-subquery-in-dql-class-is-not-defined. But I could not figure out. Please help.
My Query is as follows:
$filterQuery = "SELECT tempResult1.email as email,tempResult1.name as name , tempResult1.id as user
FROM (select u.email as email,a.name as name , u.id as user
FROM
Application\Entity\Userhasrole uhr
INNER JOIN
Application\Entity\Oauthrole r with uhr.applicationrole = r.id
INNER JOIN
Application\Entity\Application a with r.application = a.id
INNER JOIN
Application\Entity\Oauthusers u
) tempResult1
LEFT JOIN
(SELECT uhr1.user as user FROM Application\Entity\Userhasrole uhr1 where
a.id = :applicationId
) tempResult2
with tempResult1.user = tempResult2.user";
$queryObject = $this->getEntityManager()
->createQuery($filterQuery);
$queryObject->setParameter('applicationId', $applicationId);
$result = $queryObject->getResult();
You mix 2 concepts of Doctrine2 :
using SQL
using DQL
If you want to achieve that you want, build tables selections, and not entities selections, you should use EntityManager::createNativeQuery() method and set an SQL query as parameter.
EntityManager::createQuery() is used only for DQL queries
I have a database with account numbers and card numbers. I match these to a file to update any card numbers to the account number so that I am only working with account numbers.
I created a view linking the table to the account/card database to return the Table ID and the related account number, and now I need to update those records where the ID matches the Account Number.
This is the Sales_Import table, where the account number field needs to be updated:
LeadID
AccountNumber
147
5807811235
150
5807811326
185
7006100100007267039
And this is the RetrieveAccountNumber table, where I need to update from:
LeadID
AccountNumber
147
7006100100007266957
150
7006100100007267039
I tried the below, but no luck so far:
UPDATE [Sales_Lead].[dbo].[Sales_Import]
SET [AccountNumber] = (SELECT RetrieveAccountNumber.AccountNumber
FROM RetrieveAccountNumber
WHERE [Sales_Lead].[dbo].[Sales_Import]. LeadID =
RetrieveAccountNumber.LeadID)
It updates the card numbers to account numbers, but the account numbers get replaced by NULL
I believe an UPDATE FROM with a JOIN will help:
MS SQL
UPDATE
Sales_Import
SET
Sales_Import.AccountNumber = RAN.AccountNumber
FROM
Sales_Import SI
INNER JOIN
RetrieveAccountNumber RAN
ON
SI.LeadID = RAN.LeadID;
MySQL and MariaDB
UPDATE
Sales_Import SI,
RetrieveAccountNumber RAN
SET
SI.AccountNumber = RAN.AccountNumber
WHERE
SI.LeadID = RAN.LeadID;
The simple Way to copy the content from one table to other is as follow:
UPDATE table2
SET table2.col1 = table1.col1,
table2.col2 = table1.col2,
...
FROM table1, table2
WHERE table1.memberid = table2.memberid
You can also add the condition to get the particular data copied.
For SQL Server 2008 + Using MERGE rather than the proprietary UPDATE ... FROM syntax has some appeal.
As well as being standard SQL and thus more portable it also will raise an error in the event of there being multiple joined rows on the source side (and thus multiple possible different values to use in the update) rather than having the final result be undeterministic.
MERGE INTO Sales_Import
USING RetrieveAccountNumber
ON Sales_Import.LeadID = RetrieveAccountNumber.LeadID
WHEN MATCHED THEN
UPDATE
SET AccountNumber = RetrieveAccountNumber.AccountNumber;
Unfortunately the choice of which to use may not come down purely to preferred style however. The implementation of MERGE in SQL Server has been afflicted with various bugs. Aaron Bertrand has compiled a list of the reported ones here.
Generic answer for future developers.
SQL Server
UPDATE
t1
SET
t1.column = t2.column
FROM
Table1 t1
INNER JOIN Table2 t2
ON t1.id = t2.id;
Oracle (and SQL Server)
UPDATE
t1
SET
t1.colmun = t2.column
FROM
Table1 t1,
Table2 t2
WHERE
t1.ID = t2.ID;
MySQL
UPDATE
Table1 t1,
Table2 t2
SET
t1.column = t2.column
WHERE
t1.ID = t2.ID;
For PostgreSQL:
UPDATE Sales_Import SI
SET AccountNumber = RAN.AccountNumber
FROM RetrieveAccountNumber RAN
WHERE RAN.LeadID = SI.LeadID;
Seems you are using MSSQL, then, if I remember correctly, it is done like this:
UPDATE [Sales_Lead].[dbo].[Sales_Import] SET [AccountNumber] =
RetrieveAccountNumber.AccountNumber
FROM RetrieveAccountNumber
WHERE [Sales_Lead].[dbo].[Sales_Import].LeadID = RetrieveAccountNumber.LeadID
I had the same problem with foo.new being set to null for rows of foo that had no matching key in bar. I did something like this in Oracle:
update foo
set foo.new = (select bar.new
from bar
where foo.key = bar.key)
where exists (select 1
from bar
where foo.key = bar.key)
Here's what worked for me in SQL Server:
UPDATE [AspNetUsers] SET
[AspNetUsers].[OrganizationId] = [UserProfile].[OrganizationId],
[AspNetUsers].[Name] = [UserProfile].[Name]
FROM [AspNetUsers], [UserProfile]
WHERE [AspNetUsers].[Id] = [UserProfile].[Id];
For MySql that works fine:
UPDATE
Sales_Import SI,RetrieveAccountNumber RAN
SET
SI.AccountNumber = RAN.AccountNumber
WHERE
SI.LeadID = RAN.LeadID
Thanks for the responses. I found a solution tho.
UPDATE Sales_Import
SET AccountNumber = (SELECT RetrieveAccountNumber.AccountNumber
FROM RetrieveAccountNumber
WHERE Sales_Import.leadid =RetrieveAccountNumber.LeadID)
WHERE Sales_Import.leadid = (SELECT RetrieveAccountNumber.LeadID
FROM RetrieveAccountNumber
WHERE Sales_Import.leadid = RetrieveAccountNumber.LeadID)
In case the tables are in a different databases. (MSSQL)
update database1..Ciudad
set CiudadDistrito=c2.CiudadDistrito
FROM database1..Ciudad c1
inner join
database2..Ciudad c2 on c2.CiudadID=c1.CiudadID
Use the following block of query to update Table1 with Table2 based on ID:
UPDATE Sales_Import, RetrieveAccountNumber
SET Sales_Import.AccountNumber = RetrieveAccountNumber.AccountNumber
where Sales_Import.LeadID = RetrieveAccountNumber.LeadID;
This is the easiest way to tackle this problem.
MS Sql
UPDATE c4 SET Price=cp.Price*p.FactorRate FROM TableNamea_A c4
inner join TableNamea_B p on c4.Calcid=p.calcid
inner join TableNamea_A cp on c4.Calcid=cp.calcid
WHERE c4..Name='MyName';
Oracle 11g
MERGE INTO TableNamea_A u
using
(
SELECT c4.TableName_A_ID,(cp.Price*p.FactorRate) as CalcTot
FROM TableNamea_A c4
inner join TableNamea_B p on c4.Calcid=p.calcid
inner join TableNamea_A cp on c4.Calcid=cp.calcid
WHERE p.Name='MyName'
) rt
on (u.TableNamea_A_ID=rt.TableNamea_B_ID)
WHEN MATCHED THEN
Update set Price=CalcTot ;
update from one table to another table on id matched
UPDATE
TABLE1 t1,
TABLE2 t2
SET
t1.column_name = t2.column_name
WHERE
t1.id = t2.id;
The below SQL someone suggested, does NOT work in SQL Server. This syntax reminds me of my old school class:
UPDATE table2
SET table2.col1 = table1.col1,
table2.col2 = table1.col2,
...
FROM table1, table2
WHERE table1.memberid = table2.memberid
All other queries using NOT IN or NOT EXISTS are not recommended. NULLs show up because OP compares entire dataset with smaller subset, then of course there will be matching problem. This must be fixed by writing proper SQL with correct JOIN instead of dodging problem by using NOT IN. You might run into other problems by using NOT IN or NOT EXISTS in this case.
My vote for the top one, which is conventional way of updating a table based on another table by joining in SQL Server. Like I said, you cannot use two tables in same UPDATE statement in SQL Server unless you join them first.
This is the easiest and best have seen for Mysql and Maria DB
UPDATE table2, table1 SET table2.by_department = table1.department WHERE table1.id = table2.by_id
Note: If you encounter the following error based on your Mysql/Maria DB version "Error Code: 1175. You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column To disable safe mode, toggle the option in Preferences"
Then run the code like this
SET SQL_SAFE_UPDATES=0;
UPDATE table2, table1 SET table2.by_department = table1.department WHERE table1.id = table2.by_id
it works with postgresql
UPDATE application
SET omts_received_date = (
SELECT
date_created
FROM
application_history
WHERE
application.id = application_history.application_id
AND application_history.application_status_id = 8
);
update within the same table:
DECLARE #TB1 TABLE
(
No Int
,Name NVarchar(50)
,linkNo int
)
DECLARE #TB2 TABLE
(
No Int
,Name NVarchar(50)
,linkNo int
)
INSERT INTO #TB1 VALUES(1,'changed person data', 0);
INSERT INTO #TB1 VALUES(2,'old linked data of person', 1);
INSERT INTO #TB2 SELECT * FROM #TB1 WHERE linkNo = 0
SELECT * FROM #TB1
SELECT * FROM #TB2
UPDATE #TB1
SET Name = T2.Name
FROM #TB1 T1
INNER JOIN #TB2 T2 ON T2.No = T1.linkNo
SELECT * FROM #TB1
I thought this is a simple example might someone get it easier,
DECLARE #TB1 TABLE
(
No Int
,Name NVarchar(50)
)
DECLARE #TB2 TABLE
(
No Int
,Name NVarchar(50)
)
INSERT INTO #TB1 VALUES(1,'asdf');
INSERT INTO #TB1 VALUES(2,'awerq');
INSERT INTO #TB2 VALUES(1,';oiup');
INSERT INTO #TB2 VALUES(2,'lkjhj');
SELECT * FROM #TB1
UPDATE #TB1 SET Name =S.Name
FROM #TB1 T
INNER JOIN #TB2 S
ON S.No = T.No
SELECT * FROM #TB1
try this :
UPDATE
Table_A
SET
Table_A.AccountNumber = Table_B.AccountNumber ,
FROM
dbo.Sales_Import AS Table_A
INNER JOIN dbo.RetrieveAccountNumber AS Table_B
ON Table_A.LeadID = Table_B.LeadID
WHERE
Table_A.LeadID = Table_B.LeadID
MYSQL (This is my preferred way for restoring all specific column reasonId values, based on primary key id equivalence)
UPDATE `site` AS destination
INNER JOIN `site_copy` AS backupOnTuesday
ON backupOnTuesday.`id` = destination.`id`
SET destdestination.`reasonId` = backupOnTuesday.`reasonId`
This will allow you to update a table based on the column value not being found in another table.
UPDATE table1 SET table1.column = 'some_new_val' WHERE table1.id IN (
SELECT *
FROM (
SELECT table1.id
FROM table1
LEFT JOIN table2 ON ( table2.column = table1.column )
WHERE table1.column = 'some_expected_val'
AND table12.column IS NULL
) AS Xalias
)
This will update a table based on the column value being found in both tables.
UPDATE table1 SET table1.column = 'some_new_val' WHERE table1.id IN (
SELECT *
FROM (
SELECT table1.id
FROM table1
JOIN table2 ON ( table2.column = table1.column )
WHERE table1.column = 'some_expected_val'
) AS Xalias
)
Summarizing the other answers, there're 4 variants of how to update target table using data from another table only when "match exists"
Query and sub-query:
update si
set si.AccountNumber = (
select ran.AccountNumber
from RetrieveAccountNumber ran
where si.LeadID = ran.LeadID
)
from Sales_Import si
where exists (select * from RetrieveAccountNumber ran where ran.LeadID = si.LeadID)
Inner join:
update si
set si.AccountNumber = ran.AccountNumber
from Sales_Import si inner join RetrieveAccountNumber ran on si.LeadID = ran.LeadID
Cross join:
update si
set si.AccountNumber = ran.AccountNumber
from Sales_Import si, RetrieveAccountNumber ran
where si.LeadID = ran.LeadID
Merge:
merge into Sales_Import si
using RetrieveAccountNumber ran on si.LeadID = ran.LeadID
when matched then update set si.accountnumber = ran.accountnumber;
All variants are more-less trivial and understandable, personally I prefer "inner join" option. But any of them could be used and developer has to select "better option" according to his/her needs
From performance perspective variants with join-s are more preferable:
Oracle 11g
merge into Sales_Import
using RetrieveAccountNumber
on (Sales_Import.LeadId = RetrieveAccountNumber.LeadId)
when matched then update set Sales_Import.AccountNumber = RetrieveAccountNumber.AccountNumber;
For Oracle SQL try using alias
UPDATE Sales_Lead.dbo.Sales_Import SI
SET SI.AccountNumber = (SELECT RAN.AccountNumber FROM RetrieveAccountNumber RAN WHERE RAN.LeadID = SI.LeadID);
I'd like to add one extra thing.
Don't update a value with the same value, it generates extra logging and unnecessary overhead.
See example below - it will only perform the update on 2 records despite linking on 3.
DROP TABLE #TMP1
DROP TABLE #TMP2
CREATE TABLE #TMP1(LeadID Int,AccountNumber NVarchar(50))
CREATE TABLE #TMP2(LeadID Int,AccountNumber NVarchar(50))
INSERT INTO #TMP1 VALUES
(147,'5807811235')
,(150,'5807811326')
,(185,'7006100100007267039');
INSERT INTO #TMP2 VALUES
(147,'7006100100007266957')
,(150,'7006100100007267039')
,(185,'7006100100007267039');
UPDATE A
SET A.AccountNumber = B.AccountNumber
FROM
#TMP1 A
INNER JOIN #TMP2 B
ON
A.LeadID = B.LeadID
WHERE
A.AccountNumber <> B.AccountNumber --DON'T OVERWRITE A VALUE WITH THE SAME VALUE
SELECT * FROM #TMP1
ORACLE
use
UPDATE suppliers
SET supplier_name = (SELECT customers.customer_name
FROM customers
WHERE customers.customer_id = suppliers.supplier_id)
WHERE EXISTS (SELECT customers.customer_name
FROM customers
WHERE customers.customer_id = suppliers.supplier_id);
update table1 dpm set col1 = dpu.col1 from table2 dpu where dpm.parameter_master_id = dpu.parameter_master_id;
If above answers not working for you try this
Update Sales_Import A left join RetrieveAccountNumber B on A.LeadID = B.LeadID
Set A.AccountNumber = B.AccountNumber
where A.LeadID = B.LeadID
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
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;
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';
Or simply:
\dt to show tables
\d+ <table name> to describe a table
Edit: Works using the psql command line client
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
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.
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;
Shortcut
\d for show all tables
\d tablename to describe table
\? for more shortcuts for redshift
redshift now support show table
show table analytics.dw_users
https://forums.aws.amazon.com/ann.jspa?annID=8641
You can simply use the command below to describe a table.
desc table-name
or
desc schema-name.table-name