Mysql – Any MYSQL Client with fully dark theme

Try changing the query to force a value

Instead of

SELECT id FROM table WHERE id=${LOOKUP}

you can use

SELECT COUNT(1) FROM table WHERE id=${LOOKUP}

Here is bash script to use that new query

LOOKUP=123
SQLSTMT="SELECT COUNT(1) FROM table WHERE id=${LOOKUP}"
RCOUNT=`mysql -u... -p... -AN -Ddbname -e"${SQLSTMT}"`
if [ ${RCOUNT} -eq 0 ]
then
    echo "Row ${LOOKUP} exists"
else
    echo "Row ${LOOKUP} does not exist"
fi

Here is an alternative

LOOKUP=123
SQLSTMT="SELECT CONCAT('Row ',rcount,' ',IF(rcount=0,'Exists','Does Not Exist')) FROM (SELECT COUNT(1) rcount FROM rolando WHERE id=${LOOKUP}) A"
mysql -u... -p... -AN -Ddbname -e"${SQLSTMT}" > /tmp/answer.txt
cat /tmp/answer.txt

Give it a Try !!!

Rebooting temporarily clears the problem, and the error moves around... this strongly points to defective system RAM causing corruption of the OS cache.

InnoDB: It is also possible that your operating
InnoDB: system has corrupted its own file cache
InnoDB: and rebooting your computer removes the
InnoDB: error.

You likely already know this part, but with Ubuntu, on startup, select "Memory test (memtest86+)" to verify. If you don't normally see the GRUB boot menu, you should be able to hold left-shift as it first starts up.