wp core install database connection error

I am new to wordpress but not to programming to please bear with me. I am trying to get a new wordpress project up and running locally using the wp-cli.

But when I run the following command:

wp core install --url=example.com --title=WP-EXAMPLE --admin_user=******* --admin_password=****** --admin_email=******

I get the following error:

Error: Error establishing a database connection. This either means that the username and password information in your `wp-config.php` file is incorrect or we can’t contact the database server at `localhost`. This could mean your host’s database server is down.

I was able to run the wp config create and wp db create commands without issue and a database was create so I know that the database username and password are correct. Is there a step I am missing?

The output of wp --info is as follows:

OS: Darwin 17.6.0 Darwin Kernel Version 17.6.0: Tue May  8 15:22:16 PDT 2018; root:xnu-4570.61.1~1/RELEASE_X86_64 x86_64
Shell:  /bin/zsh
PHP binary: /usr/bin/php
PHP version:    7.1.16
php.ini used:
WP-CLI root dir:    phar://wp-cli.phar
WP-CLI vendor dir:  phar://wp-cli.phar/vendor
WP_CLI phar path:   /Users/admin/code/wp-example
WP-CLI packages dir:
WP-CLI global config:
WP-CLI project config:
WP-CLI version: 1.5.1

Since there are so many blank items I feel as though I am missing something although I have following all of the steps that I have found in quick start guides for setting up wordpress from the CLI.

Thanks in advance.

First ensure the normal browser install works. If not, here’s a really good article on that: How to Fix the Error Establishing a Database Connection in WordPress.

Next thing to note is that your database may not be hosted on localhost. Then try to create the wp-config.php using 127.0.0.1 or 127.0.0.1:8889 (for MAMP for example) or something similar. On an existing installation this can be fixed by replacing the DB_HOST with define('DB_HOST', '127.0.0.1:8889'); in your wp-config.php.

For an existing site you could also try it with define('WP_ALLOW_REPAIR', true); in your wp-config.php and then access the site in a browser to let WordPress fix some common database issues for you.

The article also suggest to create a raw testconnection.php file in your WordPress root (replaced the database credentials with yours) and call that in a browser http://example.com/testconnection.php to see what will be returned:

<?php
$link = mysqli_connect('localhost', 'username', 'password');
if (!$link) {
  die('Could not connect: ' . mysqli_error());
}
echo 'Connected successfully';
mysqli_close($link);
?>