Paste columns of different MySQL tables into an ascii file - mysql

Question

I have hundreds of MySQL tables, and I would like to create an ascii table with the first column of each MySQL table.
From MySQL tables
table A table B ... table Z
A1 A2 A3 B1 B2 B3 Z1 Z2 Z3
A1 A2 A3 B1 B2 B3 Z1 Z2 Z3
A1 A2 A3 B1 B2 B3 Z1 Z2 Z3
to an ascii file
A1 B1 ... Z1
A1 B1 ... Z1
A1 B1 ... Z1
Which is the faster method?
The tables are hundreds, the columns have thousands of lines, and most of all the columns have the same number of lines (so I don't think that a "join" before the export is necessary)
Thanks a lot

Answer 1

I am not a bash expert but I do things step wise (Other experts can edit and improve my answer)
#!/bin/bash
mysql -uusrname -ppassword -Ddatabasename -s -e 'show tables'
count=0
while read tablenames
do
fieldname=$(mysql -uusrname -ppassword -Ddatabasename -s -e "desc $tablename" | head -2 | tail -1 | awk -F " " '{print $1}');
echo "$tablenames,$fieldname" >> tempfile
done< $(mysql -uusrname -ppassword -Ddatabasename -s -e 'show tables')
lastcount=$(wc -l tempfile)
while read line
do
count=$(($count + 1))
if [ $count -eq 1 ]
then
echo "nothing to do"
elif [ $count -lt $lastcount ]
then
echo $line | awk -F "," '{print "(select "$2 "from" $1")"}' >> sqlcommand.sql
echo "union" >> sqlcommand.sql
else
echo $line | awk -F "," '{print "(select "$2 "from" $1");"}' >> sqlcommand.sql
done < tempfile
mysql -uusrname -ppassword -Ddatabasename << sqlcommand.sql >> outputasciifile.txt