使用 while read 将 MySQL 查询中的空变量设置为 false

Question

MySQL-Version: mysql Ver 15.1 Distrib 10.2.31-MariaDB, for Linux (x86_64) using readline 5.1 Bash-Version: GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu)

I'm using the following code with Bash to do a MySQL query.

The value of "ssl" in the MySQL Database is empty (I check that with the condition SELECT * FROM domains WHERE ssl=')

while read ssl certificate_id; do

echo $ssl
echo $certificate_id

done < <(mysql -NB -utheuser -pthemysqlpass psa -e  "SELECT ssl, certificate_id FROM domains WHERE id='26';")

If ssl is empty in the database, the read command will ignore or skip this variable and set the value of certificate_id to ssl.

I tried a lot of variants using IFS= but it didn't work.

I want to set the value of "ssl" to "false" if "ssl" is empty.

Do you have an idea how to do that?

Thanks!

Answer 1

I think that I found an alternative using the IF function of MySQL:

SELECT IF(ssl = '', 'false', ssl) ssl, certificate_id FROM domains WHERE id='26';"

I have to do more tests using bash but the first tests using PHPMyAdmin gave the correct result.

Maybe it will help others!