title: How can connect psql with normal user without specifying database name?
body: <p>I can connect mysql with username without specifying any database name,<code>showkey</code> is one of mysql user:</p>
  <pre><code>mysql -u showkey -p
  Enter password: 
  Welcome to the MariaDB monitor.  Commands end with ; or \g.
  Your MariaDB connection id is 14
  Server version: 10.3.31-MariaDB-0+deb10u1 Debian 10
  </code></pre>
  <p>Now i log into mysql without specifying any database name.<code>showkey</code> is also a normal user for my postgresql,<code>test</code> is a database name in my postgresql.</p>
  <pre><code>psql -d test -U showkey
  Timing is on.
  Pager usage is off.
  Null display is &quot;missing data&quot;.
  psql (11.14 (Debian 11.14-0+deb10u1))
  Type &quot;help&quot; for help.
  
  test=# 
  </code></pre>
  <p>I conncet the <code>test</code> database with a normal user <code>showkey</code>,now want to connect postgresql with normal user without specifying database name such way as in mysql:</p>
  <pre><code>psql -U showkey
  psql: FATAL:  database &quot;showkey&quot; does not exist
  </code></pre>
  <p><code>sudo -u postgres psql</code> can connect postgresql with a super user instead of with normal user.</p>