store postgresql result in bash variable

Question

How to atore a scalar postgresql-value on a bash-variable like in script below?

dbname="testlauf"
username="postgres"

vartest='psql -c -d $dbname -U $username -h localhost -p 5432 "SELECT gid FROM testtable WHERE aid='1';"'
echo "$vartest"

I tried several different writings, but nothing seems to work. Thanks in advance.

Answer 1

Put the -c option just before its argument - the query. Mind also using the additional -t option to get just the tuple value. And of course, use the backticks (`) operator.

Using the -X option is also recommended, as sometimes a .psqlrc file might add some redundant output, as well as the -A option, which disables column aligning (whitespaces).

vartest=`psql -X -A -d $dbname -U $username -h localhost -p 5432 -t -c "SELECT gid FROM testtable WHERE aid='1'"`