Check if mysql database exists, perform action based on result

Question

Is it possible from within a bash script to check if a mysql database exists. Depending on the result then perform another action or terminate the script?

Answer 1

If it helps, I did this for MariaDB on Debian Stretch:

DB_CHECK=$(mysqlshow "${DB_NAME}" | grep "Unknown database") 1> /dev/null
if [ ! -z "${DB_CHECK}" ]; then
    echo "Database found."
else
    echo "Database not found."
fi

Short explanation: The result of mysqlshow for database name in variable $DB_NAME is checked for "Unknown database". If that string is found it's put into variable $DB_CHECK. Then finally the -z comparison checks if the $DB_CHECK variable is empty.

If $DB_CHECK is empty then "Unknown database" did not appear in the mysqlshow response. Probably not 100% reliable, like if the connection failed or whatever. (I've not tested that.)