SQ="'\\''"
SQE="'\\\''"

:0
* DATA ?? .
{ 
  DATA="`echo \"$DATA\" \
    | sed -re 's,'\'','$SQE$SQE',g;' \
          -e  's/^.*$/'\$SQE'&'\$SQE'/' \
          -e  's/,'$SQE'$/'\$SQE',/'`"
}

:0 E
{ LOG="sql-escape:  WARNING: no \$DATA provided!$NL" }

SQE
SQ