SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.148 2004/01/19 04:57:53 jplyon Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.

**
** This statement is parsed up as follows:
**
**     SELECT c FROM t3
**      |
**      `----->  SELECT b FROM t2
**                |
**                `------>  SELECT a FROM t1
**
** The arrows in the diagram above represent the Select.pPrior pointer.
** So if this routine is called with p equal to the t3 query, then
** pPrior will be the t2 query.  p->op will be TK_UNION in this case.
**
** Notice that because of the way SQLite parses compound SELECTs, the
** individual selects always group from left to right.

**
**     SRT_Mem         Store first result in memory cell iParm
**
**     SRT_Set         Store results as keys of a table with cursor iParm
**
**     SRT_Union       Store results as a key in a temporary table iParm
**
**     SRT_Except      Remove results from the temporary table iParm.
**
**     SRT_Table       Store results in temporary table iParm
**
** The table above is incomplete.  Additional eDist value have be added
** since this comment was written.  See the selectInnerLoop() function for
** a complete listing of the allowed values of eDest and their meanings.
**