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Re: [sql] Select embeded in join [message #22844 is a reply to message #22840]

Fri, 21 August 2009 15:59

Zbych
Messages: 326
Registered: July 2009

Senior Member

luzr wrote on Fri, 21 August 2009 14:30

Would it be possible to use other type as return value?

All joins expect SqlId type, so it can be any type that can be converted to SqlId. I tried it with String and it works fine:

String   AsTable(SqlId table) const               { return String("(") << text << ") as " << table.ToString(); }

But maybe all joins should be overloaded and accept SqlSelect?

Sqlexp.h:

class SqlSelect {
[...]
private:
	SqlSelect& LeftJoin0(const char * item);
[...]
public:
	SqlSelect& LeftJoin(SqlId table) {return LeftJoin0(~table);}
	SqlSelect& LeftJoin(SqlSelect select) {return LeftJoin0(~select);}
[...]
	String   ToString() const { return text; }
	String   operator~() const { return ToString(); }
[...]
	SqlSelect & AsTable(SqlId table);
[...]


SqlStatement.cpp:

SqlSelect& SqlSelect::LeftJoin0(const char * item) {
	text << " left outer join " << item;
	return *this;
}


SqlSelect & SqlSelect::AsTable(SqlId table)		          
{
	text = String("(") <<  text << ") as " << ~table;
	return *this;
}

[Updated on: Fri, 21 August 2009 21:57]

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