diff --git a/mysql-test/main/case.result b/mysql-test/main/case.result
index 1fd1ad86a8e..926ac000eb0 100644
--- a/mysql-test/main/case.result
+++ b/mysql-test/main/case.result
@@ -546,5 +546,32 @@ Warnings:
 Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` = 'a'
 DROP TABLE t1;
 #
+# MDEV-17411 Wrong WHERE optimization with simple CASE and searched CASE
+#
+CREATE TABLE t1 (a INT, b INT, KEY(a));
+INSERT INTO t1 VALUES (1,1),(2,2),(3,3);
+SELECT * FROM t1 WHERE CASE a WHEN b THEN 1 END=1;
+a	b
+1	1
+2	2
+3	3
+SELECT * FROM t1 WHERE CASE WHEN a THEN b ELSE 1 END=3;
+a	b
+3	3
+SELECT * FROM t1 WHERE
+CASE      a WHEN b THEN 1 END=1 AND
+CASE WHEN a THEN b ELSE 1 END=3;
+a	b
+3	3
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE
+CASE      a WHEN b THEN 1 END=1 AND
+CASE WHEN a THEN b ELSE 1 END=3;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where (case `test`.`t1`.`a` when `test`.`t1`.`b` then 1 end) = 1 and (case when `test`.`t1`.`a` then `test`.`t1`.`b` else 1 end) = 3
+DROP TABLE t1;
+#
 # End of 10.3 test
 #
diff --git a/mysql-test/main/case.test b/mysql-test/main/case.test
index d7dac112b3b..78d5b3a5951 100644
--- a/mysql-test/main/case.test
+++ b/mysql-test/main/case.test
@@ -390,6 +390,28 @@ EXPLAIN EXTENDED SELECT * FROM t1 WHERE a='a' AND CASE 'a' WHEN 'a' THEN 'a' ELS
 
 DROP TABLE t1;
 
+
+--echo #
+--echo # MDEV-17411 Wrong WHERE optimization with simple CASE and searched CASE
+--echo #
+
+CREATE TABLE t1 (a INT, b INT, KEY(a));
+INSERT INTO t1 VALUES (1,1),(2,2),(3,3);
+SELECT * FROM t1 WHERE CASE a WHEN b THEN 1 END=1;
+SELECT * FROM t1 WHERE CASE WHEN a THEN b ELSE 1 END=3;
+
+SELECT * FROM t1 WHERE
+  CASE      a WHEN b THEN 1 END=1 AND
+  CASE WHEN a THEN b ELSE 1 END=3;
+
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE
+  CASE      a WHEN b THEN 1 END=1 AND
+  CASE WHEN a THEN b ELSE 1 END=3;
+
+DROP TABLE t1;
+
+
 --echo #
 --echo # End of 10.3 test
 --echo #
diff --git a/sql/item.h b/sql/item.h
index 6823d58a94c..d743cf6c19c 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -2211,6 +2211,15 @@ protected:
     }
     return true;
   }
+  bool eq(const Item_args *other, bool binary_cmp) const
+  {
+    for (uint i= 0; i < arg_count ; i++)
+    {
+      if (!args[i]->eq(other->args[i], binary_cmp))
+        return false;
+    }
+    return true;
+  }
 public:
   Item_args(void)
     :args(NULL), arg_count(0)
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 4a7a44b3399..92f1391c9f8 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -1813,10 +1813,7 @@ bool Item_func_opt_neg::eq(const Item *item, bool binary_cmp) const
     return 0;
   if (negated != ((Item_func_opt_neg *) item_func)->negated)
     return 0;
-  for (uint i=0; i < arg_count ; i++)
-    if (!args[i]->eq(item_func->arguments()[i], binary_cmp))
-      return 0;
-  return 1;
+  return Item_args::eq(item_func, binary_cmp);
 }
 
 
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
index b34bf1dde19..60b56090a23 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -2154,6 +2154,7 @@ public:
     DBUG_ASSERT(arg_count >= 2);
     reorder_args(0);
   }
+  enum Functype functype() const   { return CASE_SEARCHED_FUNC; }
   void print(String *str, enum_query_type query_type);
   bool fix_length_and_dec();
   Item *propagate_equal_fields(THD *thd, const Context &ctx, COND_EQUAL *cond)
@@ -2206,6 +2207,7 @@ public:
     Predicant_to_list_comparator::cleanup();
     DBUG_VOID_RETURN;
   }
+  enum Functype functype() const   { return CASE_SIMPLE_FUNC; }
   void print(String *str, enum_query_type query_type);
   bool fix_length_and_dec();
   Item *propagate_equal_fields(THD *thd, const Context &ctx, COND_EQUAL *cond);
diff --git a/sql/item_func.cc b/sql/item_func.cc
index 3dcfe4fbce8..c5ac97f2905 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -647,10 +647,7 @@ bool Item_func::eq(const Item *item, bool binary_cmp) const
       (func_type == Item_func::FUNC_SP &&
        my_strcasecmp(system_charset_info, func_name(), item_func->func_name())))
     return 0;
-  for (uint i=0; i < arg_count ; i++)
-    if (!args[i]->eq(item_func->args[i], binary_cmp))
-      return 0;
-  return 1;
+  return Item_args::eq(item_func, binary_cmp);
 }
 
 
diff --git a/sql/item_func.h b/sql/item_func.h
index 1d19c7a43f1..fd789ffdc51 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -76,7 +76,10 @@ public:
                   SUSERVAR_FUNC, GUSERVAR_FUNC, COLLATE_FUNC,
                   EXTRACT_FUNC, CHAR_TYPECAST_FUNC, FUNC_SP, UDF_FUNC,
                   NEG_FUNC, GSYSVAR_FUNC, IN_OPTIMIZER_FUNC, DYNCOL_FUNC,
-                  JSON_EXTRACT_FUNC };
+                  JSON_EXTRACT_FUNC,
+                  CASE_SEARCHED_FUNC, // Used by ColumnStore/Spider
+                  CASE_SIMPLE_FUNC    // Used by ColumnStore/spider
+                };
   enum Type type() const { return FUNC_ITEM; }
   virtual enum Functype functype() const   { return UNKNOWN_FUNC; }
   Item_func(THD *thd): Item_func_or_sum(thd)