I was testing efficacy of a paid Database security solution which has the ability to detect and block SQLi attack. For the testing purpose I have tried the following query against a PostgreSQL database through this tool which act as a proxy.

select * from test where id=1 or 1=1;

For this query the tool were able to detect and block. But then I tried another one

select * from test where id=1 or true;

But this time the query got infiltrated and got the full table data as result.

Isn't it a classical example of SQLi? What type of queries are actually considered as SQLi which I can test against the tool?

  • 1
    The typical SQL injection query contains at least four single quotes, because it works by interpolating a string between single quotes. I would be very wary of any tool that claims to recognize such queries. It will either miss some statements or report false positives or both. Dec 1, 2023 at 8:19
  • IMO, double hyphen -- somewhere in the middle of the query could be a sign of sql injection, especially if the part have been commented out contains something similar to sql, the semicolon ; could be a sign of sql injection as well. Dec 1, 2023 at 9:24
  • Why would you use statements like that and not filter/clean out user input ? If you really want to be sure then use only stored procedures for data access. Dec 1, 2023 at 13:01
  • If that is what you want to protect against, then you have already done the test and the tool failed. What more do you need to know?
    – jjanes
    Dec 1, 2023 at 22:42
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    @BasilTitus the task of proving that particular SQL query is malicious seems to be hard, for example, in your case or 1=1 looks suspicious from tool's perspective, however it fails on PostgreSQL grammar where or true is valid statement, the problem is there is a zillion of options to write "always true statement", does your tool recognise something like or exists (select * from pg_class) for example? IMO, the tool should have built-in SQL engine in order to be able to detect anomalies in SQL queries, that is definitely much simpler to develop PostgreSQL extension. Dec 6, 2023 at 3:17

1 Answer 1


This isn't a Sql Injection attack.
This is: (obligatory XKCD Reference) "Little Bobby Tables".

I'm not entirely sure what this is trying to protect against ...

... or 1 = 1 ...

I've seen several Management Information applications that build dynamic Sql where clauses using exactly this construct (and then appending other, 'and'ed conditions after it).

where 1 = 1 
and ... 
and ... 

Lazy coding, but quick and easy.

If Row-Based security is done properly, this wouldn't gain the attacker anyway because they would only gain access to all of the rows that they were allowed to see anyway - effectively, all SQL runs against an already-filtered dataset.

  • I bet the given example of sql injection query was based on SQL Injection from OWASP Dec 1, 2023 at 9:31
  • The 1 = 1; (notice the semicolon terminator) is a common pattern used with SQL injections (at least many moons ago, idk what's commonplace anymore) as a way to cleanly terminate the orginal valid SQL statement with a valid clause, so that then additional SQL statements could be injected directly after without breaking the original SQL statement from a bad syntax error, ensuring the injected commands ran successfully. I imagine whatever tool OP is using, is just blindly looking for that exact predicate, which is obviously a false positive in many cases.
    – J.D.
    Dec 1, 2023 at 13:42
  • You turn WHERE id=98356 into WHERE id=98356 or 1=1 and now you get back the entire table rather rather than the small part of it you were supposed to get back.
    – jjanes
    Dec 1, 2023 at 22:46
  • You can put 1=1 and AND together, no problem even if it's useless statement.But why would someone put or 1=1 at the end of a statement unless it's an attack, if i want full data i just query the table without where clause.
    – mediocre
    Dec 4, 2023 at 8:40

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