E: Package 'Mysql-Client' Has No Installation Candidate in Php-Fpm Image Build Using Docker Compose

Im fairly new to docker and so im trying to learn more about it using a laravel project, im following this tutorial:

Ive adjusted the Dockerfile a bit from what the tutorial has but even the tutorial file causes the same result.

FROM php:7.3-fpm

# Copy composer.lock and composer.json
COPY composer.lock composer.json /var/www/
# Install dependencies
RUN curl -sL  | bash - && \
    apt-get update && apt-get install -y mysql-client \
    

RUN npm install -g npm

# Clear cache
RUN apt-get clean && rm -rf /var/lib/apt/lists/*


# Install extensions
RUN docker-php-ext-install pdo pdo_mysql

# Install composer
RUN curl -sS  | php -- --install-dir=/usr/local/bin --filename=composer

# Add user for laravel application
RUN groupadd -g 1000 www
RUN useradd -u 1000 -ms /bin/bash -g www www

# Copy existing application directory contents
COPY . /var/www

# Copy existing application directory permissions
COPY --chown=www:www . /var/www

# Change current user to www
USER www
# Set working directory
WORKDIR /var/www
# Expose port 9000 and start php-fpm server
EXPOSE 9000

CMD ["php-fpm"]

But i keep getting the following error when i run docker-compose up -d:

E: Package 'mysql-client' has no installation candidate
ERROR: Service 'app' failed to build: The command '/bin/sh -c curl -sL  | bash - &&     apt-get update && apt-get install -y mysql-client     nodejs     build-essential     vim     git     curl' returned a non-zero code: 100

Am i missing something?

I expected this to work since i am running apt-get update before installing mysql-client.

Thanks.