Hey there, let's work through these PostgreSQL CREATE DATABASE problems you're hitting. I'll walk through common causes and fixes for both scenarios:

Here are the most likely culprits and how to fix them:

• Insufficient User Permissions: Your database user might lack the CREATEDB privilege. To check this, run:

  SELECT rolcreatedb FROM pg_roles WHERE rolname = 'your_username';
  

  If the result is false, switch to a superuser account (like postgres) and grant the privilege:

  ALTER ROLE your_username CREATEDB;
  

• Disk Space Exhaustion: PostgreSQL needs free disk space to create new databases. On Linux, check available space with:

  df -h
  

  On Windows, open File Explorer and check the drive hosting your PostgreSQL data directory. Free up space if it's full.
• PostgreSQL Service Not Running: If the database service is stopped, no operations will work. On Linux, verify status with:

  sudo systemctl status postgresql
  

  On Windows, go to Services (via services.msc) and ensure the PostgreSQL service is running. Restart it if needed.
• Corrupted Template Database: PostgreSQL uses template1 as the default template for new databases. If it's corrupted, try creating a database using template0 instead:

  CREATE DATABASE your_db_name TEMPLATE template0;
  

  If that works, you can rebuild template1 from template0 to fix the underlying issue.

When using quoted identifiers, these are the common issues to check:

• Duplicate Database Name: The database you're trying to create might already exist. Verify this with:

  SELECT 1 FROM pg_database WHERE datname = 'databasename';
  

  If a result returns, either choose a new name or drop the existing database first (with caution!):

  DROP DATABASE "databasename";
  

• Invalid Database Name (Even with Quotes): Quoted identifiers can include special characters, but they can't contain null bytes or exceed 63 bytes in length. Double-check your database name for invalid characters or excessive length.
• Incorrect Quote Type: Make sure you're using English double quotes ("), not Chinese quotes or single quotes. Single quotes are for string literals, not database identifiers.
• Permission or Disk Issues: Same as the first issue—ensure your user has CREATEDB privileges and there's enough free disk space.

If you can share the exact error message from your screenshot, we can narrow this down even further!

内容的提问来源于stack exchange，提问作者Chandra Suriya M