Script with multiline string and for loop - bash

Question

Writing a quick script for a temporary/repetitive task. Wrote a basic solution that works:
for thing in "$#";
do
/usr/mysql/bin/mysql -u xyz -p pdq <<END;
UPDATE table
SET table_atr = 'NW'
WHERE record_id = $thing
END
done
This works but forces a password check for every member of argument array (not ideal).
Tried to update it to this:
if {$# -le 1}; then
for thing in "$#";
do
/usr/mysql/bin/mysql -u xyz -p pdq <<END;
UPDATE table
SET table_atr = 'NW'
WHERE record_id = $thing
END
done
else
things = ""
for thing in "$#";
do
things += "$thing"
if {$thing == $#[$# - 1]}; then
things += "\n"
continue
else
things += ",\n"
done
/usr/mysql/bin/mysql -u xyz -p pdq <<END;
UPDATE table
SET table_atr = 'NW'
WHERE record_id IN
(
$things
)
END
TLDR: If there is more than one argument: do a for loop to fill a WHERE .. IN () statement. I realize this doesn't even need to be a multiline string and maybe that is my issue but the error I'm getting is (apparently) unrealted .
The error I get is:
line 24: syntax error near unexpected token' done'
line 24: ' done'
Neither I, nor my supervisor have much experience with shell scripts but I cannot see any syntax error with the 2nd for loop. Its exactly the same as the first which executes fine.
Any help is greatly appreciated, I may just have to go to the basic version or write this as a Perl script instead. Thanks!

Answer 1

Thanks everyone for all the advice. This was an edit that worked:
#!/bin/sh
if [ $# -le 1 ]; then
for thing in "$#";
do
/usr/mysql/bin/mysql -u xyz -p pdq <<END;
UPDATE table
SET table_atr = 'NW'
WHERE record_id = $thing
END
done
else
things=""
i=1
for thing in "$#";
do
things+="$thing"
if [ $i -eq $# ]; then
things+=""
else
things+=", "
fi
((i+=1))
done
/usr/mysql/bin/mysql -u xyz -p pdq <<END;
UPDATE table
SET table_atr = 'NW'
WHERE record_id IN ($things)
END
fi
There were indeed many syntax errors and changing the WHERE .. IN () string construction to a single line made this a lot easier. Luckily I didn't have to worry about inserting single quotes, mysql took the query without them.
I came out of this with a much higher respect for bash scripting. It is a serious language that requires its own study and I will approach it with much more attention to detail in the future.
Thanks again.