How to Combine fields in AdoQuery sql statement in delphi? - delphi

Question

with AdoQuery do
begin
Close;
SQL.Clear;
SQL.Add('SELECT (name+' '+surname+' '+father) as initihal, address from user');
Open;
end;
How to add space between name surname and father ?
i want to see result in DbGrid like that
Lionel Andrés Messi

Answer 1

The ADO layer/backend server should be fine with returning a column value which is an expression including a number of column values and string literals.
As you are trying to construct your SQL statement in Delphi source code (rarely a good idea, ime) you need to express what you want in a way which is syntactically correct from the compiler's point of view, as well as producing the desired result from your RDMS. To do this, all of the single quotes inside SQL.Add(...) except the outer two need to be doubled-up, otherwise you will get a syntax error on compilation.
However, even once you've done that, your SQL still may not execute correctly at run-time depending on whether your naming of the columns in your result-set is digestible by your back-end server. It's best to create and test your Select statement using whatever query tool is available for your RDMS, then attempt to set it up in Delphi only after you've got it working correctly from the RDMS's pov.
Btw, you will encounter fewer problems if you get into the habit of using the QuotedStr function in constructing the column values you want - you obviously need the syntax practice so I leave you to look that up in the Online Help.
Also, if you need to constrain the result set by specifying a Where clause, be sure to do it in a way which minimizes the risk of Sql Injection (https://en.wikipedia.org/wiki/SQL_injection) which arises when the SQL includes input text from the user. The bet way to do this is to use a parameterized Where clause.

Answer 2

If using inline SQL you have escape the quote characters or use a function that returns spaces. You will not be able to update the result. Another option is to add a calculated field in your Delphi ADOQuery component and do the combine client side in OnCalcFields.
with AdoQuery do
begin
Close;
SQL.Clear;
SQL.Add('SELECT name+'' ''+surname+'' ''+father as initihal, address from user');
Open;
end;
If using SQL Server for a database you can use the space() function.
with AdoQuery do
begin
Close;
SQL.Clear;
SQL.Add('SELECT name+ space(1) + surname+ space(1) +father as initihal, address from user');
Open;
end;