Here is my best guess...

Try using 'integer' as the data type for PersonID.  The error message seems to be indicating the column where the data type starts.

When using ODBC, you must use SQL statements that conform to the ODBC driver requirements for the database's ODBC driver.  ODBC has its own SQL grammar rules that may constrict the SQL grammar usable.  This is an issue connected to ODBC, not InstantSQL.  

When looking at the PostgresSQL grammar, 'int' is not a supported SQL data type, but 'integer' is.

So, when you are testing a query outside of InstantSQL, you should be using an ODBC testing environment.  On Windows, use ODBC Test from Microsoft (https://learn.microsoft.com/en-us/sql/odbc/odbc-test?view=sql-server-ver16).  If you are on Linux, then the ODBC test environment depends on your version of ODBC driver manager (UnixODBC or Iodbc).  By using one of these ODBC testing environments, you can test without the 'noise' that InstantSQL adds.

(Sorry, no PostgresSQL available here.)

Thank you Tom. As you mentioned above, the problem seems to be with ISQL (my ODBC test in linux). 

While using ISQL in  linux for POSTGRES, I am able to make a connection to the database and execute select/update/insert/delete statements on tables.

But I am unable to execute create/drop/grant statements. I tried with ini, integer etc but still does not work. the drop and grant also does not work.

I am getting error as below,

1.CREATE

SQL> create table shop (item1 integer);
[S1000]ERROR:  syntax error at or near "create" at character 29;
Error while executing the query
[ISQL]ERROR: Could not SQLExecute
SQL> create table shop (item1 int);
[S1000]ERROR:  syntax error at or near "create" at character 29;
Error while executing the query
[ISQL]ERROR: Could not SQLExecute

2.DROP

SQL> drop table persons2;
[S1000]ERROR:  syntax error at or near "drop" at character 29;
Error while executing the query
[ISQL]ERROR: Could not SQLExecute

3.SELECT

SQL> select * from persons2;

| personid   | pname                                                                                                                                                                                                                                                        
+------------+---------------------------------------------------------- 
------------+
| 1          | test1                                                                                                                                                                                                                                                        
| 2          | test2                                                                                                                                                                                                                                                          
| 3          | test3                                                                                                                                                                                                                                                          
| 4          | test4                                                                                                                                                                                                                                                          
SQLRowCount returns 4
4 rows fetched

Grant statement does not work as well.  Please find my permissions below

SQL> SELECT rolname, rolsuper, rolcreaterole FROM pg_roles WHERE rolname 
= 'me';
+-----------+---------+--------------+
| rolname   | rolsuper| rolcreaterole|
+-----------+---------+--------------+
| me        | 1       | 0            |
+-----------+---------+--------------+

I am able to execute all the above statements using PSQL  though,

psqltest=# create table shop(item1 int);

CREATE TABLE

Is there any other permissions needed for executing DDL statements using ISQL?

Your results indicate you would probably be more likely to find a solution in a postgresSQL support forum.  A less likely possibility might be a unixODBC support forum.  Since you have eliminated InstantSQL from your debug environment, you should be able to pursue support in these other sites without the 'stigma' of COBOL.

It is curious that the syntax error message always indicates character 29.

It doesn't look like the unixODBC tool isql has any way to make calls to the ODBC API.  (Microsoft's ODBCTEST does allow this.)  

The fact that you can execute statements using psql is not overly significant.  The SQL syntax for ODBC is different from 'native' Postgres SQL.  The ODBC minimal SQL grammar does not include the GRANT statement.  In the ODBC CREATE TABLE statement, column data types have to match the data types  returned by the API call SQLGetTypeInfo, which do not necessarily match the column data types in the native Postgres syntax.  ODBC minimal grammar is defined here.

Anyway, the good news is that this problem can be simplified in a way that it can be presented in one of the other suggest support sites, and that InstantSQL is not a contributor to the problem.

The issue got resolved when I connected to ISQL without the username and password. 

In this case too it created a table under my userid but when I logged in with my userid it did not let me create the table (not sure why).

SQL CONNECT DATASOURCE
sql-ConnectionHandle
"dbname".

rather than,

SQL CONNECT DATASOURCE
sql-ConnectionHandle
"dbname"

 "userid"

 "password".

ie. I connect to isql directly as > ISQL dbname 

instead of > ISQL dbname userid password