Easiest way to get count val from mysql in bash

Maybe i should use python or perl but i dont know any.

I have 4 statements and i would like to check if there are any errors longer then an hour. My user is setup so i dont need to enter a mysql user/pass. This statement is in mysql_webapp_error_check.sh

#!/bin/bash
mysql testdb -e "select count(*) from tbl where last_error_date < DATE_SUB(NOW(), INTERVAL 1  HOUR);"

How do i make it give 开发者_开发技巧me the return value (count(*)) instead of printing to screen?

Then i'll write an if statement and output to stdout/err for cron to use to email me (otherwise i want the script to be silent so nothing is emailed unless theres a problem)

---

Searched the same, -s for silent works exactly for me.

#!/bin/bash
result=`mysql testdb -s -e "select count(*) from tbl where last_error_date < DATE_SUB(NOW(), INTERVAL 1  HOUR);"`
echo result = .$result.

PS.: There is also a --batch parameter in my mysql Ver 14.14 Distrib 5.1.49 which "Write fields without conversion. Used with --batch" so its a little off-topic here, but should be mentioned here.

---

in bash, you use $() syntax.

#!/bin/bash
ret=$(mysql testdb -e "select count(*) from tbl where last_error_date < DATE_SUB(NOW(), INTERVAL 1  HOUR);")
if [[ "$ret" > 0 ]];then
   echo "there is count"
else
   echo "no count"
fi

---

I usually do this:

 var=`mysql -e "SELECT COUNT(*) FROM ...\G" | awk '/COUNT/{print $2}/'`

---

For my part I simply use grep -v to exclude the line printing count(*) from the return of MySQL.

So I get the counter like that:

db_name="NAME_DB";
db_user="USER_DB";
db_pwd="PWD_DB";
counter=`mysql -u${db_user} -p${db_pwd} ${db_name} -e "SELECT count(*) FROM my_table WHERE something = '1';" | grep -v "count"`;
echo "Count for request: $counter";

I use it for some Wordpress stuff this way, reading databases infos from the wp-config.php file:

wp_db_infos="wp-config.php";
wp_db=`cat ${wp_db_infos} | grep "DB_NAME" | awk -F ', ' '{print $2}' | awk -F "'" '{print $2}'`;
wp_user=`cat ${wp_db_infos} | grep "DB_USER" | awk -F ', ' '{print $2}' | awk -F "'" '{print $2}'`;
wp_pwd=`cat ${wp_db_infos} | grep "DB_PASSWORD" | awk -F ', ' '{print $2}' | awk -F "'" '{print $2}'`;
img_to_update=`mysql -u${wp_user} -p${wp_pwd} ${wp_db} -e "SELECT count(*) FROM wp_offres WHERE maj_img = '1';" | grep -v "count"`;

---

#!/bin/bash
echo show databases\; | mysql -u root | (while read x; do
  echo "$x"
  y="$x"
done
echo "$y"
)

---

local count=$(mysql -u root --disable-column-names --batch --execute "SELECT COUNT(*) FROM mysql.user WHERE user = '$DstDbName'")
    if [[ "$count" > 0 ]]
    then
    fi          

--batch - do clear output w/o borders --disable-column-names - prints only row with value

no creasy AWK used :)