Eliminate the need for the Column.zDflt (using Column.pDflt instead) to reduce
the amount of memory needed to hold the schema.

FossilOrigin-Name: d8c94a46dfa94930732c2de2aa79675c5087d36e
diff --git a/src/treeview.c b/src/treeview.c
index ff3b4be..907159c 100644
--- a/src/treeview.c
+++ b/src/treeview.c
@@ -339,6 +339,12 @@
     case TK_ISNULL:  zUniOp = "ISNULL"; break;
     case TK_NOTNULL: zUniOp = "NOTNULL"; break;
 
+    case TK_SPAN: {
+      sqlite3TreeViewLine(pView, "SPAN %Q", pExpr->u.zToken);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+
     case TK_COLLATE: {
       sqlite3TreeViewLine(pView, "COLLATE %Q", pExpr->u.zToken);
       sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);