diff --git a/mysql-test/r/alter_table.result b/mysql-test/r/alter_table.result
index f714e6646de..207f6166fe0 100644
--- a/mysql-test/r/alter_table.result
+++ b/mysql-test/r/alter_table.result
@@ -1354,7 +1354,7 @@ CREATE TABLE t1 (
 id INT(11) NOT NULL,
 x_param INT(11) DEFAULT NULL,
 PRIMARY KEY (id)
-);
+) ENGINE=MYISAM;
 ALTER TABLE t1 ADD COLUMN IF NOT EXISTS id INT,
 ADD COLUMN IF NOT EXISTS lol INT AFTER id;
 Warnings:
@@ -1390,6 +1390,77 @@ t1	CREATE TABLE `t1` (
   KEY `x_param1` (`x_param`)
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 DROP TABLE t1;
+CREATE TABLE t1 (
+id INT(11) NOT NULL,
+x_param INT(11) DEFAULT NULL,
+PRIMARY KEY (id)
+) ENGINE=INNODB;
+CREATE TABLE t2 (
+id INT(11) NOT NULL) ENGINE=INNODB;
+ALTER TABLE t1 ADD COLUMN IF NOT EXISTS id INT,
+ADD COLUMN IF NOT EXISTS lol INT AFTER id;
+Warnings:
+Note	1060	Duplicate column name 'id'
+ALTER TABLE t1 ADD COLUMN IF NOT EXISTS lol INT AFTER id;
+Warnings:
+Note	1060	Duplicate column name 'lol'
+ALTER TABLE t1 DROP COLUMN IF EXISTS lol;
+ALTER TABLE t1 DROP COLUMN IF EXISTS lol;
+Warnings:
+Note	1091	Can't DROP 'lol'; check that column/key exists
+ALTER TABLE t1 ADD KEY IF NOT EXISTS x_param(x_param);
+ALTER TABLE t1 ADD KEY IF NOT EXISTS x_param(x_param);
+Warnings:
+Note	1061	Duplicate key name 'x_param'
+ALTER TABLE t1 MODIFY IF EXISTS lol INT;
+Warnings:
+Note	1054	Unknown column 'lol' in 't1'
+DROP INDEX IF EXISTS x_param ON t1;
+DROP INDEX IF EXISTS x_param ON t1;
+Warnings:
+Note	1091	Can't DROP 'x_param'; check that column/key exists
+CREATE INDEX IF NOT EXISTS x_param1 ON t1(x_param);
+CREATE INDEX IF NOT EXISTS x_param1 ON t1(x_param);
+Warnings:
+Note	1061	Duplicate key name 'x_param1'
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `id` int(11) NOT NULL,
+  `x_param` int(11) DEFAULT NULL,
+  PRIMARY KEY (`id`),
+  KEY `x_param1` (`x_param`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+ALTER TABLE t2 ADD FOREIGN KEY IF NOT EXISTS fk(id) REFERENCES t1(id);
+ALTER TABLE t2 ADD FOREIGN KEY IF NOT EXISTS fk(id) REFERENCES t1(id);
+Warnings:
+Note	1061	Duplicate key name 'fk'
+ALTER TABLE t2 DROP FOREIGN KEY IF EXISTS fk;
+ALTER TABLE t2 DROP FOREIGN KEY IF EXISTS fk;
+Warnings:
+Note	1091	Can't DROP 'fk'; check that column/key exists
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `id` int(11) NOT NULL,
+  KEY `fk` (`id`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+ALTER TABLE t2 ADD FOREIGN KEY (id) REFERENCES t1(id);
+ALTER TABLE t2 ADD FOREIGN KEY IF NOT EXISTS t2_ibfk_1(id) REFERENCES t1(id);
+Warnings:
+Note	1061	Duplicate key name 't2_ibfk_1'
+ALTER TABLE t2 DROP FOREIGN KEY IF EXISTS t2_ibfk_1;
+ALTER TABLE t2 DROP FOREIGN KEY IF EXISTS t2_ibfk_1;
+Warnings:
+Note	1091	Can't DROP 't2_ibfk_1'; check that column/key exists
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `id` int(11) NOT NULL,
+  KEY `id` (`id`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+DROP TABLE t2;
+DROP TABLE t1;
 #
 # Bug#11938817 ALTER BEHAVIOR DIFFERENT THEN DOCUMENTED
 #
diff --git a/mysql-test/t/alter_table.test b/mysql-test/t/alter_table.test
index 2053e2d9d59..3050fc0378d 100644
--- a/mysql-test/t/alter_table.test
+++ b/mysql-test/t/alter_table.test
@@ -1258,7 +1258,7 @@ CREATE TABLE t1 (
   id INT(11) NOT NULL,
   x_param INT(11) DEFAULT NULL,
   PRIMARY KEY (id)
-);
+) ENGINE=MYISAM;
 
 ALTER TABLE t1 ADD COLUMN IF NOT EXISTS id INT,
                ADD COLUMN IF NOT EXISTS lol INT AFTER id;
@@ -1277,6 +1277,45 @@ CREATE INDEX IF NOT EXISTS x_param1 ON t1(x_param);
 SHOW CREATE TABLE t1;
 DROP TABLE t1;
 
+CREATE TABLE t1 (
+  id INT(11) NOT NULL,
+  x_param INT(11) DEFAULT NULL,
+  PRIMARY KEY (id)
+) ENGINE=INNODB;
+
+CREATE TABLE t2 (
+  id INT(11) NOT NULL) ENGINE=INNODB;
+
+ALTER TABLE t1 ADD COLUMN IF NOT EXISTS id INT,
+               ADD COLUMN IF NOT EXISTS lol INT AFTER id;
+ALTER TABLE t1 ADD COLUMN IF NOT EXISTS lol INT AFTER id;
+ALTER TABLE t1 DROP COLUMN IF EXISTS lol;
+ALTER TABLE t1 DROP COLUMN IF EXISTS lol;
+
+ALTER TABLE t1 ADD KEY IF NOT EXISTS x_param(x_param);
+ALTER TABLE t1 ADD KEY IF NOT EXISTS x_param(x_param);
+ALTER TABLE t1 MODIFY IF EXISTS lol INT;
+
+DROP INDEX IF EXISTS x_param ON t1;
+DROP INDEX IF EXISTS x_param ON t1;
+CREATE INDEX IF NOT EXISTS x_param1 ON t1(x_param);
+CREATE INDEX IF NOT EXISTS x_param1 ON t1(x_param);
+SHOW CREATE TABLE t1;
+
+ALTER TABLE t2 ADD FOREIGN KEY IF NOT EXISTS fk(id) REFERENCES t1(id);
+ALTER TABLE t2 ADD FOREIGN KEY IF NOT EXISTS fk(id) REFERENCES t1(id);
+ALTER TABLE t2 DROP FOREIGN KEY IF EXISTS fk;
+ALTER TABLE t2 DROP FOREIGN KEY IF EXISTS fk;
+SHOW CREATE TABLE t2;
+ALTER TABLE t2 ADD FOREIGN KEY (id) REFERENCES t1(id);
+ALTER TABLE t2 ADD FOREIGN KEY IF NOT EXISTS t2_ibfk_1(id) REFERENCES t1(id);
+ALTER TABLE t2 DROP FOREIGN KEY IF EXISTS t2_ibfk_1;
+ALTER TABLE t2 DROP FOREIGN KEY IF EXISTS t2_ibfk_1;
+SHOW CREATE TABLE t2;
+
+DROP TABLE t2;
+DROP TABLE t1;
+
 --echo #
 --echo # Bug#11938817 ALTER BEHAVIOR DIFFERENT THEN DOCUMENTED
 --echo #
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 45d9c5dc091..bd43dfff478 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -5304,7 +5304,8 @@ handle_if_exists_options(THD *thd, TABLE *table, Alter_info *alter_info)
           {
             alter_info->flags&= ~Alter_info::ALTER_ADD_COLUMN;
             if (alter_info->key_list.is_empty())
-              alter_info->flags&= ~Alter_info::ALTER_ADD_INDEX;
+              alter_info->flags&= ~(Alter_info::ALTER_ADD_INDEX |
+                                    Alter_info::ADD_FOREIGN_KEY);
           }
           break;
         }
@@ -5379,13 +5380,32 @@ handle_if_exists_options(THD *thd, TABLE *table, Alter_info *alter_info)
       else /* Alter_drop::KEY */
       {
         uint n_key;
-        for (n_key=0; n_key < table->s->keys; n_key++)
+        if (drop->type != Alter_drop::FOREIGN_KEY)
         {
-          if (my_strcasecmp(system_charset_info,
-                            drop->name, table->key_info[n_key].name) == 0)
+          for (n_key=0; n_key < table->s->keys; n_key++)
           {
-            remove_drop= FALSE;
-            break;
+            if (my_strcasecmp(system_charset_info,
+                  drop->name, table->key_info[n_key].name) == 0)
+            {
+              remove_drop= FALSE;
+              break;
+            }
+          }
+        }
+        else
+        {
+          List <FOREIGN_KEY_INFO> fk_child_key_list;
+          FOREIGN_KEY_INFO *f_key;
+          table->file->get_foreign_key_list(thd, &fk_child_key_list);
+          List_iterator<FOREIGN_KEY_INFO> fk_key_it(fk_child_key_list);
+          while ((f_key= fk_key_it++))
+          {
+            if (my_strcasecmp(system_charset_info, f_key->foreign_id->str,
+                  drop->name) == 0)
+            {
+              remove_drop= FALSE;
+              break;
+            }
           }
         }
       }
@@ -5397,7 +5417,8 @@ handle_if_exists_options(THD *thd, TABLE *table, Alter_info *alter_info)
         drop_it.remove();
         if (alter_info->drop_list.is_empty())
           alter_info->flags&= ~(Alter_info::ALTER_DROP_COLUMN |
-                                Alter_info::ALTER_DROP_INDEX);
+                                Alter_info::ALTER_DROP_INDEX  |
+                                Alter_info::DROP_FOREIGN_KEY);
       }
     }
   }
@@ -5408,6 +5429,7 @@ handle_if_exists_options(THD *thd, TABLE *table, Alter_info *alter_info)
     Key *key;
     List_iterator<Key> key_it(alter_info->key_list);
     uint n_key;
+    bool remove_key;
     const char *keyname;
     while ((key=key_it++))
     {
@@ -5424,24 +5446,48 @@ handle_if_exists_options(THD *thd, TABLE *table, Alter_info *alter_info)
         if (keyname == NULL)
           continue;
       }
-      for (n_key=0; n_key < table->s->keys; n_key++)
+      remove_key= FALSE;
+      if (key->type != Key::FOREIGN_KEY)
       {
-        if (my_strcasecmp(system_charset_info,
-              keyname, table->key_info[n_key].name) == 0)
+        for (n_key=0; n_key < table->s->keys; n_key++)
         {
-          push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
-              ER_DUP_KEYNAME, ER(ER_DUP_KEYNAME), keyname);
-          key_it.remove();
-          if (key->type == Key::FOREIGN_KEY)
+          if (my_strcasecmp(system_charset_info,
+                keyname, table->key_info[n_key].name) == 0)
           {
-            /* ADD FOREIGN KEY appends two items. */
-            key_it.remove();
+            remove_key= TRUE;
+            break;
           }
-          if (alter_info->key_list.is_empty())
-            alter_info->flags&= ~Alter_info::ALTER_ADD_INDEX;
-          break;
         }
       }
+      else
+      {
+        List <FOREIGN_KEY_INFO> fk_child_key_list;
+        FOREIGN_KEY_INFO *f_key;
+        table->file->get_foreign_key_list(thd, &fk_child_key_list);
+        List_iterator<FOREIGN_KEY_INFO> fk_key_it(fk_child_key_list);
+        while ((f_key= fk_key_it++))
+        {
+          if (my_strcasecmp(system_charset_info, f_key->foreign_id->str,
+                key->name.str) == 0)
+            remove_key= TRUE;
+            break;
+        }
+      }
+      if (remove_key)
+      {
+        push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
+            ER_DUP_KEYNAME, ER(ER_DUP_KEYNAME), key->name.str);
+        key_it.remove();
+        if (key->type == Key::FOREIGN_KEY)
+        {
+          /* ADD FOREIGN KEY appends two items. */
+          key_it.remove();
+        }
+        if (alter_info->key_list.is_empty())
+          alter_info->flags&= ~(Alter_info::ALTER_ADD_INDEX |
+              Alter_info::ADD_FOREIGN_KEY);
+        break;
+      }
     }
   }
   
diff --git a/storage/innobase/dict/dict0dict.cc b/storage/innobase/dict/dict0dict.cc
index 1a1697b2ffc..d16296179b0 100644
--- a/storage/innobase/dict/dict0dict.cc
+++ b/storage/innobase/dict/dict0dict.cc
@@ -4238,18 +4238,45 @@ loop:
 		goto loop;
 	}
 
+	if (my_isspace(cs, *ptr)) {
+                ptr1 = dict_accept(cs, ptr, "IF", &success);
+
+                if (success) {
+                        if (!my_isspace(cs, *ptr1)) {
+                                goto loop;
+                        }
+                        ptr1 = dict_accept(cs, ptr1, "NOT", &success);
+                        if (!success) {
+                                goto loop;
+                        }
+                        ptr1 = dict_accept(cs, ptr1, "EXISTS", &success);
+                        if (!success) {
+                                goto loop;
+                        }
+                        ptr = ptr1;
+                }
+	}
+
 	ptr = dict_accept(cs, ptr, "(", &success);
 
 	if (!success) {
-		/* MySQL allows also an index id before the '('; we
-		skip it */
-		ptr = dict_skip_word(cs, ptr, &success);
+                if (constraint_name) {
+		  /* MySQL allows also an index id before the '('; we
+		  skip it */
+		  ptr = dict_skip_word(cs, ptr, &success);
+		  if (!success) {
+			  dict_foreign_report_syntax_err(
+				  name, start_of_latest_foreign, ptr);
+                          return(DB_CANNOT_ADD_CONSTRAINT);
+                  }
+		}
+                else {
+		  while (my_isspace(cs, *ptr)) {
+			  ptr++;
+		  }
 
-		if (!success) {
-			dict_foreign_report_syntax_err(
-				name, start_of_latest_foreign, ptr);
-
-			return(DB_CANNOT_ADD_CONSTRAINT);
+		  ptr = dict_scan_id(cs, ptr, heap,
+				     &constraint_name, FALSE, FALSE);
 		}
 
 		ptr = dict_accept(cs, ptr, "(", &success);
@@ -4723,6 +4750,7 @@ dict_foreign_parse_drop_constraints(
 	char*			str;
 	size_t			len;
 	const char*		ptr;
+        const char*             ptr1;
 	const char*		id;
 	struct charset_info_st*	cs;
 
@@ -4773,6 +4801,16 @@ loop:
 		goto syntax_error;
 	}
 
+	ptr1 = dict_accept(cs, ptr, "IF", &success);
+
+	if (success && my_isspace(cs, *ptr1)) {
+	        ptr1 = dict_accept(cs, ptr1, "EXISTS", &success);
+	        if (success) {
+
+                        ptr = ptr1;
+	        }
+	}
+
 	ptr = dict_scan_id(cs, ptr, heap, &id, FALSE, TRUE);
 
 	if (id == NULL) {