How do I change all empty strings to NULL in a table?

Question

I have a legacy table with about 100 columns (90% nullable). In those 90 columns I want to remove all empty strings and set them to null. I know I can:

updat         


        

Answer 1

One possible script:

for col in $(echo "select column_name from information_schema.columns
where table_name='$TABLE'"|mysql --skip-column-names $DB)
do
echo update $TABLE set $col = NULL where $col = \'\'\;
done|mysql $DB