Shell Programming and Scripting

#! /bin/sh

#for each table in tables_list get all column_names
for table in `cat tables_list`
do
        ctr=0
        echo "\ntable name is $table"
        for col in `grep $table columns_list | awk {'print $2'}`
        do
                ((ctr=ctr+1))
                echo "column $ctr name is $col"
        done
done

BEGIN { SEPlist="," }
FNR==NR { tbl[$1]; next}
{ 
  if ( $1 in tbl )
     out[$1] = ($1 in out) ? out[$1] SEPlist $2 : $2
}
END {
   for ( i in out)
      print i, out[i]
}

table_1 connection1
table_2 connection2
table_3 connection3

BEGIN { SEPlist="," }
FNR==NR { tbl[$1]; next}
{ 
  if ( $1 in tbl )
     out[$1] = ($1 in out) ? out[$1] SEPlist $2 : $2
}
END {
   for ( i in out)
      printf("select %s from %s@connection1\n",  out[i], i)
}

BEGIN { 
    SEPlist="," 
    schemasN=split("connection1 connection2 connection3 connection4", schemasA, " ")
}
FNR==NR { tbl[$1]; next}
{ 
  if ( $1 in tbl )
     out[$1] = ($1 in out) ? out[$1] SEPlist $2 : $2
}
END {
   for(s=2; s <= schemasN; s++) 
     for ( i in out)
        printf("select %s from %s@%s\nminus\nselect %s from %s@%s\n",  out[i], i, schemasA[1], out[i], i, schemasA[s])
}