如何在SQL脚本中使用Perl变量（使用反引号）

Question

I have seen various examples but I am unable to use DBI. How would I use a perl variable in an external sql script? For example the code in the perl script I would want would be:

$text = 'Germany';
@sql_output = `sqlplus -s user/pass\@databasename <<!
 @/pathtofile/test.sql;
  QUIT;
  !`;
print @sql_output;

The sql script would be:

SELECT DISTINCT City FROM Customers
Where Country = '$text'

(Just as an example, I'm using the code comes from w3schools.com sql tutorial http://www.w3schools.com/SQl/trysql.asp?filename=trysql_select_distinct )

An example that I found through searching had:

@/pathtofile/test.sql $text;

But it did not work when I tried it with my code. Is this the correct way to incorporate a perl variable into an external sql script?

Answer 1

1. Define your replacement variable(s)
2. Use them in a here doc based on the content of your test.sql
3. Save it to test.sql
4. Execute your backtick command

OR

• If you want to learn basic SQL: Install a DBMS with a GUI that allows interactive/ad hoc queries (eg SQLite/SQliteman/SQLite browser plugin, MySQL/MySQLWorkbench, Access, OO/LO Base, ...)
• If you want to work with Oracle: Concentrate on a complete/working install (which includes DBD:Oracle if your scripting language is Perl)

Answer 2

This one works, basically the flow is as below

1. Open the SQL File
2. Replace the $text with the variable value
3. Write it to the temporary file
4. Execute SQL plus on the temporary file (Every time when you re-run this it will replace the file)

Try out and let me know.

test.pl

#!/usr/bin/perl

$text = 'Germany1';
open(HEADER,"SQLQuery.sql");
while(<HEADER>) { $_ =~ s/\$text/$text/g; $output .= $_; }
close(HEADER);

print "$output";


open (MYFILE, '>SQLQueryTemp.sql'); 

print MYFILE $output;

close(MYFILE);

#SQLQueryTemp.sql contains the $text replaced with 'Germany'

#@sql_output = `sqlplus -s user/pass\@databasename <<!
 #@/pathtofile/SQLQueryTemp.sql;
  #QUIT;
  #!`;
#print @sql_output;

SQLQuery.sql

SELECT DISTINCT City FROM Customers
Where Country = '$text'