Store mysql result in a bash array variable

Question

I am trying to store MySQL result into a global bash array variable but I don't know how to do it.

Should I save the MySQL command result in a file and read the file line by line in my for loop for my other treatment?

Example:

user password
Pierre aaa
Paul bbb

Command:

$results = $( mysql –uroot –ppwd –se  « SELECT * from users );

I want that results contains the two rows.

Answer 1

Mapfile for containing whole table into one bash variable

You could try this:

mapfile result < <(mysql –uroot –ppwd –se  "SELECT * from users;")

Than

echo ${result[0]%$'\t'*}
echo ${result[0]#*$'\t'}

or

for row in "${result[@]}";do
    echo Name:  ${row%$'\t'*}  pass: ${row#*$'\t'}
done

Nota This will work fine while there is only 2 fields by row. More is possible but become tricky

Read for reading table row by row

while IFS=$'\t' read name pass ;do
    echo name:$name pass:$pass
  done  < <(mysql -uroot –ppwd –se  "SELECT * from users;")

Read and loop to hold whole table into many variables:

i=0
while IFS=$'\t' read name[i] pass[i++];do
    :;done  < <(mysql -uroot –ppwd –se  "SELECT * from users;")

echo ${name[0]} ${pass[0]}
echo ${name[1]} ${pass[1]}

New (feb 2018) shell connector

There is a little tool (on github) or on my own site: (shellConnector.sh you could use:

Some preparation:

cd /tmp/
wget -q http://f-hauri.ch/vrac/shell_connector.sh
. shell_connector.sh
newSqlConnector /usr/bin/mysql '–uroot –ppwd'

Following is just for demo, skip until test for quick run

Thats all. Now, creating temporary table for demo:

echo $SQLIN
3

cat >&3 <<eof
CREATE TEMPORARY TABLE users (
  id bigint(20) unsigned NOT NULL PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(30), date DATE)
eof
myMysql myarray ';'
declare -p myarray
bash: declare: myarray: not found

The command myMysql myarray ';' will send ; then execute inline command, but as mysql wont anwer anything, variable $myarray wont exist.

cat >&3 <<eof
  INSERT INTO users VALUES (1,'alice','2015-06-09 22:15:01'),
       (2,'bob','2016-08-10 04:13:21'),(3,'charlie','2017-10-21 16:12:11')
eof
myMysql myarray ';'
declare -p myarray
bash: declare: myarray: not found

Operational Test:

Ok, then now:

myMysql myarray "SELECT * from users;"
printf "%s\n" "${myarray[@]}"
1   alice   2015-06-09
2   bob     2016-08-10
3   charlie 2017-10-21

declare -p myarray
declare -a myarray=([0]=$'1\talice\t2015-06-09' [1]=$'2\tbob\t2016-08-10' [2]=$'3\tcharlie\t2017-10-21')

This tool are in early step of built... You have to manually clear your variable before re-using them:

unset myarray
myMysql myarray "SELECT name from users where id=2;"
echo $myarray
bob

declare -p myarray
declare -a myarray=([0]="bob")

Answer 2

1. If you're looking to get a global variable inside your script you can simply assign a value to a varname:

   VARNAME=('var' 'name') # no space between the variable name and value
   

   Doing this you'll be able to access VARNAME's value anywhere in your script after you initialize it.

2. If you want your variable to be shared between multiple scripts you have to use export:

   script1.sh:

   export VARNAME=('var' 'name')
   echo ${VARNAME[0]} # will echo 'var'
   

   script2.sh

   echo ${VARNAME[1]} # will echo 'name', provided that 
                      # script1.sh was executed prior to this one
   

NOTE that export will work only when running scripts in the same shell instance. If you want it to work cross-instance you would have to put the export variable code somewhere in .bashrc or .bash_profile

Answer 3

The answer from @F. Hauri seems really complicated.

https://stackoverflow.com/a/38052768/470749 helped me realize that I needed to use parentheses () wrapped around the query result to treat is as an array.

#You can ignore this function since you'll do something different.
function showTbl {
    echo $1;
}

MOST_TABLES=$(ssh -vvv -t -i ~/.ssh/myKey ${SERVER_USER_AND_IP} "cd /app/ && docker exec laradock_mysql_1 mysql -u ${DB} -p${REMOTE_PW} -e 'SELECT table_name FROM information_schema.tables WHERE table_schema = \"${DB}\" AND table_name NOT LIKE \"pma_%\" AND table_name NOT IN (\"mail_webhooks\");'")
#Do some string replacement to get rid of the query result header and warning. https://stackoverflow.com/questions/13210880/replace-one-substring-for-another-string-in-shell-script
warningToIgnore="mysql\: \[Warning\] Using a password on the command line interface can be insecure\."
MOST_TABLES=${MOST_TABLES/$warningToIgnore/""}
headerToIgnore="table_name"
MOST_TABLES=${MOST_TABLES/$headerToIgnore/""}

#HERE WAS THE LINE THAT I NEEDED TO ADD! Convert the string to array:
MOST_TABLES=($MOST_TABLES)
for i in ${MOST_TABLES[@]}; do
    if [[ $i = *[![:space:]]* ]]
    then          
        #Remove whitespace from value https://stackoverflow.com/a/3232433/470749
        i="$(echo -e "${i}" | tr -d '[:space:]')"  
        TBL_ARR+=("$i")
    fi
done
for t in ${TBL_ARR[@]}; do        
    showTbl $t
done

This successfully shows me that ${TBL_ARR[@]} has all the values from the query result.

Answer 4

results=($( mysql –uroot –ppwd –se "SELECT * from users" ))
if [ "$?" -ne 0 ]
then
  echo fail
  exit
fi