Firedac select working with Firebird returns no records

问题

Hello I'm working with Firedac (Delphi Seattle) using Firebird (2.5) as a database, when I run this query using a TFDQuery, no records are returned:

SELECT ID FROM USERS WHERE PWD = 'êHÆ–!+'

The same query within a Database program as IbExpert return one record. Is there some parameter with Firedac components to configure that can solve this issue. Thanks.

回答1:

It's in the query string and it's the ! char. By default, query strings are preprocessed, and you must escape constant chars like !, &, :, ?, { or }, otherwise they are used as special chars.

Your best option is using parameters. That will (except other benefits) get rid of that ! char from the preprocessed command:

FDQuery.SQL.Text := 'SELECT ID FROM USERS WHERE PWD = :Password';
FDQuery.ParamByName('Password').AsString := 'êHÆ–!+';
FDQuery.Open;

Another option is escaping that constant char or disable macro preprocessor. For more information see the Special Character Processing topic.

来源：https://stackoverflow.com/questions/43465988/firedac-select-working-with-firebird-returns-no-records