commit 2c492061ceef5a52cc21fd9cfd206dd36b43bfa2
author drh <drh@noemail.net> Sat Mar 24 13:24:02 2018 +0000
committer drh <drh@noemail.net> Sat Mar 24 13:24:02 2018 +0000
tree 57a93b17c4666e948529207cfc89dbb177510803
parent b873f4e404e9205209b279827ad49eac11dfadbb

Bug fix in the LEFT JOIN strength reduction optimization of
check-in [dd568c27b1d76563].  The sqlite3ExprImpliesNotNull() routine was
mistakenly assuming that a CASE expression must always be NULL if contained
any reference to a variable that was NULL.

FossilOrigin-Name: cf171abe954a5f25262161dd69f2e8cecdbf9446c3f6b298201507dbc743567e

src/expr.c

diff --git a/src/expr.c b/src/expr.c
index 0bb7a8d..c09c0c5 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -5012,6 +5012,7 @@
     case TK_ISNULL:
     case TK_IS:
     case TK_OR:
+    case TK_CASE:
     case TK_FUNCTION:
     case TK_AGG_FUNCTION:
       return WRC_Prune;