U++ forum: Welcome to the forum

Re: How to join two tables from two schemas with SqlExp [message #50849 is a reply to message #50841]

Wed, 09 January 2019 09:22

mirek
Messages: 14267
Registered: November 2005

Ultimate Member

Patisab wrote on Tue, 08 January 2019 15:06

So is it possible? If it is, how?

#include <Core/Core.h>
#include <plugin/sqlite3/Sqlite3.h>

using namespace Upp;

CONSOLE_APP_MAIN
{
	Sqlite3Session sqlite3;
	
	sqlite3.SetTrace();
	
	SQL = sqlite3;

	SqlId T1("T1"), Col1("Col1"), Col2("Col2");
	SQLID(T2); SQLID(S2);

	SQL * Select(T1(Col1), T1(Col2), T2(Col2), T2(Col2))
	      .From(T1)
	      .InnerJoin(S2(T1).As(T2))
	      .On(T2(Col1) == T1(Col2));
}

produces

select T1.Col1, T1.Col2, T2.Col2, T2.Col2 from T1 inner join S2.T1 T2 on T2.Col1 = T1.Col2

SQLID(T1) and SqlId T1("T1") are equivalent. Also, if you are using .sch files, you can do the same thing by adding '_' to type (like INT_ (Col1) or TABLE_(T1)).

Col1.Of(T1) and T1(Col1) are equivalent (parenthesis form is 'more modern').

You cannot write "S2.T1" - we cannot support that, as C++ does not have "operator." overloading Smile

Mirek

[Updated on: Wed, 09 January 2019 09:23]

Report message to a moderator