Index: src/build.c
==================================================================
--- src/build.c
+++ src/build.c
@@ -1963,23 +1963,22 @@
       sqlite3VdbeAddOp3(v, OP_OpenWrite, 1, pParse->regRoot, iDb);
       sqlite3VdbeChangeP5(v, OPFLAG_P2ISREG);
       pParse->nTab = 2;
       addrTop = sqlite3VdbeCurrentAddr(v) + 1;
       sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
-      sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
-      sqlite3Select(pParse, pSelect, &dest);
-      sqlite3VdbeEndCoroutine(v, regYield);
-      sqlite3VdbeJumpHere(v, addrTop - 1);
-      if( pParse->nErr ) return;
       pSelTab = sqlite3ResultSetOfSelect(pParse, pSelect);
       if( pSelTab==0 ) return;
       assert( p->aCol==0 );
       p->nCol = pSelTab->nCol;
       p->aCol = pSelTab->aCol;
       pSelTab->nCol = 0;
       pSelTab->aCol = 0;
       sqlite3DeleteTable(db, pSelTab);
+      sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
+      sqlite3Select(pParse, pSelect, &dest);
+      sqlite3VdbeEndCoroutine(v, regYield);
+      sqlite3VdbeJumpHere(v, addrTop - 1);
       addrInsLoop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
       VdbeCoverage(v);
       sqlite3VdbeAddOp3(v, OP_MakeRecord, dest.iSdst, dest.nSdst, regRec);
       sqlite3TableAffinity(v, p, 0);
       sqlite3VdbeAddOp2(v, OP_NewRowid, 1, regRowid);

Index: src/select.c
==================================================================
--- src/select.c
+++ src/select.c
@@ -1379,22 +1379,21 @@
   char const *zOrigCol = 0;
 #endif
 
   assert( pExpr!=0 );
   assert( pNC->pSrcList!=0 );
+  assert( pExpr->op!=TK_AGG_COLUMN );  /* This routine runes before aggregates
+                                       ** are processed */
   switch( pExpr->op ){
-    case TK_AGG_COLUMN:
     case TK_COLUMN: {
       /* The expression is a column. Locate the table the column is being
       ** extracted from in NameContext.pSrcList. This table may be real
       ** database table or a subquery.
       */
       Table *pTab = 0;            /* Table structure column is extracted from */
       Select *pS = 0;             /* Select the column is extracted from */
       int iCol = pExpr->iColumn;  /* Index of column in pTab */
-      testcase( pExpr->op==TK_AGG_COLUMN );
-      testcase( pExpr->op==TK_COLUMN );
       while( pNC && !pTab ){
         SrcList *pTabList = pNC->pSrcList;
         for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
         if( j<pTabList->nSrc ){
           pTab = pTabList->a[j].pTab;
@@ -1703,16 +1702,16 @@
       Expr *pColExpr = sqlite3ExprSkipCollate(pEList->a[i].pExpr);
       while( pColExpr->op==TK_DOT ){
         pColExpr = pColExpr->pRight;
         assert( pColExpr!=0 );
       }
-      if( (pColExpr->op==TK_COLUMN || pColExpr->op==TK_AGG_COLUMN)
-       && pColExpr->pTab!=0 
-      ){
+      assert( pColExpr->op!=TK_AGG_COLUMN );
+      if( pColExpr->op==TK_COLUMN ){
         /* For columns use the column name name */
         int iCol = pColExpr->iColumn;
         Table *pTab = pColExpr->pTab;
+        assert( pTab!=0 );
         if( iCol<0 ) iCol = pTab->iPKey;
         zName = iCol>=0 ? pTab->aCol[iCol].zName : "rowid";
       }else if( pColExpr->op==TK_ID ){
         assert( !ExprHasProperty(pColExpr, EP_IntValue) );
         zName = pColExpr->u.zToken;

Index: test/colname.test
==================================================================
--- test/colname.test
+++ test/colname.test
@@ -375,10 +375,31 @@
   execsql2 {SELECT t1.a AS n, v3.a FROM t1 JOIN v3}
 } {n 1 a 3}
 do_test colname-9.210 {
   execsql2 {SELECT t1.a, v3.a AS n FROM t1 JOIN v3}
 } {a 1 n 3}
+
+# 2017-12-23:  Ticket https://www.sqlite.org/src/info/3b4450072511e621
+# Inconsistent column names in CREATE TABLE AS
+#
+# Verify that the names of columns in the created table of a CREATE TABLE AS
+# are the same as the names of result columns in the SELECT statement.
+#
+do_execsql_test colname-9.300 {
+  DROP TABLE IF EXISTS t1;
+  DROP TABLE IF EXISTS t2;
+  CREATE TABLE t1(aaa INT);
+  INSERT INTO t1(aaa) VALUES(123);
+}
+do_test colname-9.310 {
+  execsql2 {SELECT BBb FROM (SELECT aaa AS Bbb FROM t1)}
+} {Bbb 123}
+do_execsql_test colname-9.320 {
+  CREATE TABLE t2 AS SELECT BBb FROM (SELECT aaa AS Bbb FROM t1);
+  SELECT name FROM pragma_table_info('t2');
+} {Bbb}
+
 
 # Make sure the quotation marks get removed from the column names
 # when constructing a new table from an aggregate SELECT.
 # Email from Juergen Palm on 2017-07-11.
 #