SQLite

  if( pPrior ) pPrior->pNext = pNew;
  pNew->pNext = 0;
  pNew->pLimit = sqlite3ExprDup(db, p->pLimit, flags);
  pNew->pOffset = sqlite3ExprDup(db, p->pOffset, flags);
  pNew->iLimit = 0;
  pNew->iOffset = 0;
  pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;

  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->addrOpenEphm[2] = -1;
  pNew->nSelectRow = p->nSelectRow;
  pNew->pWith = withDup(db, p->pWith);
  return pNew;
}

%type select {Select*}
%destructor select {sqlite3SelectDelete(pParse->db, $$);}
%type selectnowith {Select*}
%destructor selectnowith {sqlite3SelectDelete(pParse->db, $$);}
%type oneselect {Select*}
%destructor oneselect {sqlite3SelectDelete(pParse->db, $$);}

select(A) ::= with(W) selectnowith(X). {
  Select *p = X, *pNext, *pLoop;
  if( p ){
    int cnt = 0, mxSelect;
    p->pWith = W;
    if( p->pPrior ){
      pNext = 0;
      for(pLoop=p; pLoop; pNext=pLoop, pLoop=pLoop->pPrior, cnt++){
        pLoop->pNext = pNext;
        pLoop->selFlags |= SF_Compound;
      }
      mxSelect = pParse->db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
      if( mxSelect && cnt>mxSelect ){
        sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
      }
    }
  }else{
    sqlite3WithDelete(pParse->db, W);
  }
  A = p;
}

selectnowith(A) ::= oneselect(X).                      {A = X;}
%ifndef SQLITE_OMIT_COMPOUND_SELECT
selectnowith(A) ::= selectnowith(X) multiselect_op(Y) oneselect(Z).  {
  if( Z ){
    Z->op = (u8)Y;

*/
void sqlite3SelectDelete(sqlite3 *db, Select *p){
  if( p ){
    clearSelect(db, p);
    sqlite3DbFree(db, p);
  }
}

/*
** Return a pointer to the right-most SELECT statement in a compound.
*/
static Select *findRightmost(Select *p){
  while( p->pNext ) p = p->pNext;
  return p;
}

/*
** Given 1 to 3 identifiers preceding the JOIN keyword, determine the
** type of join.  Return an integer constant that expresses that type
** in terms of the following bit values:
**
**     JT_INNER

    p->selFlags |= SF_UsesEphemeral;
  }

  /* Detach the ORDER BY clause from the compound SELECT */
  p->pOrderBy = 0;

  /* Store the results of the setup-query in Queue. */
  pSetup->pNext = 0;
  rc = sqlite3Select(pParse, pSetup, &destQueue);
  pSetup->pNext = p;
  if( rc ) goto end_of_recursive_query;

  /* Find the next row in the Queue and output that row */
  addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, iQueue, addrBreak);

  /* Transfer the next row in Queue over to Current */
  sqlite3VdbeAddOp1(v, OP_NullRow, iCurrent); /* To reset column cache */

  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
  */
  assert( p && p->pPrior );  /* Calling function guarantees this much */
  assert( (p->selFlags & SF_Recursive)==0 || p->op==TK_ALL || p->op==TK_UNION );
  db = pParse->db;
  pPrior = p->pPrior;


  dest = *pDest;
  if( pPrior->pOrderBy ){
    sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
      selectOpName(p->op));
    rc = 1;
    goto multi_select_end;
  }

      Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
      int addr;
      SelectDest uniondest;

      testcase( p->op==TK_EXCEPT );
      testcase( p->op==TK_UNION );
      priorOp = SRT_Union;
      if( dest.eDest==priorOp ){
        /* We can reuse a temporary table generated by a SELECT to our
        ** right.
        */


        assert( p->pLimit==0 );      /* Not allowed on leftward elements */
        assert( p->pOffset==0 );     /* Not allowed on leftward elements */
        unionTab = dest.iSDParm;
      }else{
        /* We will need to create our own temporary table to hold the
        ** intermediate results.
        */
        unionTab = pParse->nTab++;
        assert( p->pOrderBy==0 );
        addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);
        assert( p->addrOpenEphm[0] == -1 );
        p->addrOpenEphm[0] = addr;
        findRightmost(p)->selFlags |= SF_UsesEphemeral;
        assert( p->pEList );
      }

      /* Code the SELECT statements to our left
      */
      assert( !pPrior->pOrderBy );
      sqlite3SelectDestInit(&uniondest, priorOp, unionTab);

      tab1 = pParse->nTab++;
      tab2 = pParse->nTab++;
      assert( p->pOrderBy==0 );

      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
      assert( p->addrOpenEphm[0] == -1 );
      p->addrOpenEphm[0] = addr;
      findRightmost(p)->selFlags |= SF_UsesEphemeral;
      assert( p->pEList );

      /* Code the SELECTs to our left into temporary table "tab1".
      */
      sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
      explainSetInteger(iSub1, pParse->iNextSelectId);
      rc = sqlite3Select(pParse, pPrior, &intersectdest);

  if( p->selFlags & SF_UsesEphemeral ){
    int i;                        /* Loop counter */
    KeyInfo *pKeyInfo;            /* Collating sequence for the result set */
    Select *pLoop;                /* For looping through SELECT statements */
    CollSeq **apColl;             /* For looping through pKeyInfo->aColl[] */
    int nCol;                     /* Number of columns in result set */

    assert( p->pNext==0 );
    nCol = p->pEList->nExpr;
    pKeyInfo = sqlite3KeyInfoAlloc(db, nCol, 1);
    if( !pKeyInfo ){
      rc = SQLITE_NOMEM;
      goto multi_select_end;
    }
    for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){

      }
    }
  }
 
  /* Separate the left and the right query from one another
  */
  p->pPrior = 0;
  pPrior->pNext = 0;
  sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
  if( pPrior->pPrior==0 ){
    sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
  }

  /* Compute the limit registers */
  computeLimitRegisters(pParse, p, labelEnd);

  /* Reassembly the compound query so that it will be freed correctly
  ** by the calling function */
  if( p->pPrior ){
    sqlite3SelectDelete(db, p->pPrior);
  }
  p->pPrior = pPrior;
  pPrior->pNext = p;

  /*** TBD:  Insert subroutine calls to close cursors on incomplete
  **** subqueries ****/
  explainComposite(pParse, p->op, iSub1, iSub2, 0);
  return SQLITE_OK;
}
#endif

  /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
  ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
  ** because they could be computed at compile-time.  But when LIMIT and OFFSET
  ** became arbitrary expressions, we were forced to add restrictions (13)
  ** and (14). */
  if( pSub->pLimit && p->pLimit ) return 0;              /* Restriction (13) */
  if( pSub->pOffset ) return 0;                          /* Restriction (14) */
  if( (p->selFlags & SF_Compound)!=0 && pSub->pLimit ){
    return 0;                                            /* Restriction (15) */
  }
  if( pSubSrc->nSrc==0 ) return 0;                       /* Restriction (7)  */
  if( pSub->selFlags & SF_Distinct ) return 0;           /* Restriction (5)  */
  if( pSub->pLimit && (pSrc->nSrc>1 || isAgg) ){
     return 0;         /* Restrictions (8)(9) */
  }

    p->pOffset = 0;
    pNew = sqlite3SelectDup(db, p, 0);
    p->pOffset = pOffset;
    p->pLimit = pLimit;
    p->pOrderBy = pOrderBy;
    p->pSrc = pSrc;
    p->op = TK_ALL;

    if( pNew==0 ){
      p->pPrior = pPrior;
    }else{
      pNew->pPrior = pPrior;
      if( pPrior ) pPrior->pNext = pNew;
      pNew->pNext = p;

      p->pPrior = pNew;
    }
    if( db->mallocFailed ) return 1;
  }

  /* Begin flattening the iFrom-th entry of the FROM clause 
  ** in the outer query.
  */
  pSub = pSub1 = pSubitem->pSelect;

**
** This function is used as the xSelectCallback2() callback by
** sqlite3SelectExpand() when walking a SELECT tree to resolve table
** names and other FROM clause elements. 
*/
static void selectPopWith(Walker *pWalker, Select *p){
  Parse *pParse = pWalker->pParse;
  With *pWith = findRightmost(p)->pWith;
  if( pWith!=0 ){
    assert( pParse->pWith==pWith );
    pParse->pWith = pWith->pOuter;
  }
}
#else
#define selectPopWith 0
#endif

/*

    return WRC_Abort;
  }
  if( NEVER(p->pSrc==0) || (selFlags & SF_Expanded)!=0 ){
    return WRC_Prune;
  }
  pTabList = p->pSrc;
  pEList = p->pEList;
  sqlite3WithPush(pParse, findRightmost(p)->pWith, 0);

  /* Make sure cursor numbers have been assigned to all entries in
  ** the FROM clause of the SELECT statement.
  */
  sqlite3SrcListAssignCursors(pParse, pTabList);

  /* Look up every table named in the FROM clause of the select.  If

  pHaving = p->pHaving;
  sDistinct.isTnct = (p->selFlags & SF_Distinct)!=0;

#ifndef SQLITE_OMIT_COMPOUND_SELECT
  /* If there is are a sequence of queries, do the earlier ones first.
  */
  if( p->pPrior ){















    rc = multiSelect(pParse, p, pDest);
    explainSetInteger(pParse->iSelectId, iRestoreSelectId);
    return rc;
  }
#endif

  /* If there is both a GROUP BY and an ORDER BY clause and they are

  }
}
void sqlite3ExplainSelect(Vdbe *pVdbe, Select *p){
  if( p==0 ){
    sqlite3ExplainPrintf(pVdbe, "(null-select)");
    return;
  }




  sqlite3ExplainPush(pVdbe);
  while( p ){
    explainOneSelect(pVdbe, p);
    p = p->pNext;
    if( p==0 ) break;
    sqlite3ExplainNL(pVdbe);
    sqlite3ExplainPrintf(pVdbe, "%s\n", selectOpName(p->op));

  SrcList *pSrc;         /* The FROM clause */
  Expr *pWhere;          /* The WHERE clause */
  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  Select *pPrior;        /* Prior select in a compound select statement */
  Select *pNext;         /* Next select to the left in a compound */

  Expr *pLimit;          /* LIMIT expression. NULL means not used. */
  Expr *pOffset;         /* OFFSET expression. NULL means not used. */
  With *pWith;           /* WITH clause attached to this select. Or NULL. */
};

/*
** Allowed values for Select.selFlags.  The "SF" prefix stands for

#define SF_HasTypeInfo     0x0020  /* FROM subqueries have Table metadata */
#define SF_UseSorter       0x0040  /* Sort using a sorter */
#define SF_Values          0x0080  /* Synthesized from VALUES clause */
#define SF_Materialize     0x0100  /* NOT USED */
#define SF_NestedFrom      0x0200  /* Part of a parenthesized FROM clause */
#define SF_MaybeConvert    0x0400  /* Need convertCompoundSelectToSubquery() */
#define SF_Recursive       0x0800  /* The recursive part of a recursive CTE */
#define SF_Compound        0x1000  /* Part of a compound query */


/*
** The results of a SELECT can be distributed in several ways, as defined
** by one of the following macros.  The "SRT" prefix means "SELECT Result
** Type".
**

.........Jim
.........Kate
.........Lanny
.........Mary
.........Noland
.........Olivia}}

#--------------------------------------------------------------------------
# Ticket [31a19d11b97088296ac104aaff113a9790394927] (2014-02-09)
# Name resolution issue with compound SELECTs and Common Table Expressions 
#
do_execsql_test 12.1 {
WITH RECURSIVE
  t1(x) AS (VALUES(2) UNION ALL SELECT x+2 FROM t1 WHERE x<20),
  t2(y) AS (VALUES(3) UNION ALL SELECT y+3 FROM t2 WHERE y<20)
SELECT x FROM t1 EXCEPT SELECT y FROM t2 ORDER BY 1;
} {2 4 8 10 14 16 20}


finish_test