MDEV-37995: FULL OUTER JOIN name resolution

mysql-test/main/join.result

@@ -3667,17 +3667,117 @@ create table t2 (a int);
 insert into t2 (a) values (1),(2),(3);
 select * from t1 full join t2 on t1.a = t2.a;
 ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended select * from t1 full join t2 on t1.a = t2.a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+1	SIMPLE	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+Warnings:
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` full join `test`.`t2` on(multiple equal(`test`.`t1`.`a`, `test`.`t2`.`a`))
 select * from t1 full outer join t2 on t1.a = t2.a;
 ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended select * from t1 full outer join t2 on t1.a = t2.a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+1	SIMPLE	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+Warnings:
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` full join `test`.`t2` on(multiple equal(`test`.`t1`.`a`, `test`.`t2`.`a`))
 select * from t1 natural full outer join t2;
 ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended select * from t1 natural full outer join t2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+1	SIMPLE	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` natural full join `test`.`t2`
 select * from t1 natural full join t2;
 ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended select * from t1 natural full join t2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+1	SIMPLE	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` natural full join `test`.`t2`
+create view v1 as select * from t1 full join t2 on t1.a = t2.a;
+select * from v1;
+ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended select * from v1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+1	SIMPLE	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+Warnings:
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` full join `test`.`t2` on(multiple equal(`test`.`t1`.`a`, `test`.`t2`.`a`))
+drop view v1;
 create view v1 as select * from t1 full outer join t2 on t1.a = t2.a;
+select * from v1;
+ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended select * from v1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+1	SIMPLE	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+Warnings:
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` full join `test`.`t2` on(multiple equal(`test`.`t1`.`a`, `test`.`t2`.`a`))
+drop view v1;
+create view v1 as select * from t1 natural full join t2;
+select * from v1;
+ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended select * from v1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+1	SIMPLE	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` natural full join `test`.`t2`
+drop view v1;
+create view v1 as select * from t1 natural full outer join t2;
+select * from v1;
 ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended select * from v1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+1	SIMPLE	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` natural full join `test`.`t2`
+drop view v1;
+select * from (select t1.a from t1 full join t2 on t1.a = t2.a union select * from t1) dt;
+ERROR 42S22: Unknown column 't1.a' in 'SELECT'
 select * from (select t1.a from t1 full outer join t2 on t1.a = t2.a union select * from t1) dt;
+ERROR 42S22: Unknown column 't1.a' in 'SELECT'
+select * from (select t1.a from t1 natural full join t2 union select * from t1) dt;
+ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended select * from (select t1.a from t1 natural full join t2 union select * from t1) dt;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	<derived2>	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+2	DERIVED	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+2	DERIVED	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+3	UNION	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
+Warnings:
+Note	1003	/* select#1 */ select `dt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` natural full join `test`.`t2` union /* select#3 */ select `test`.`t1`.`a` AS `a` from `test`.`t1`) `dt`
+select * from (select t1.a from t1 natural full outer join t2 union select * from t1) dt;
 ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended select * from (select t1.a from t1 natural full outer join t2 union select * from t1) dt;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	<derived2>	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+2	DERIVED	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+2	DERIVED	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+3	UNION	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
+Warnings:
+Note	1003	/* select#1 */ select `dt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` natural full join `test`.`t2` union /* select#3 */ select `test`.`t1`.`a` AS `a` from `test`.`t1`) `dt`
 with cte as (select t1.a from t1 natural full join t2) select * from cte;
 ERROR 42000: This version of MariaDB doesn't yet support 'full join'
+explain extended with cte as (select t1.a from t1 natural full join t2) select * from cte;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+1	SIMPLE	t2	UNKNOWN	NULL	NULL	NULL	NULL	0	0.00	
+Warnings:
+Note	1003	with cte as (select `test`.`t1`.`a` AS `a` from `test`.`t1` natural full join `test`.`t2`)select `test`.`t1`.`a` AS `a` from `test`.`t1` natural full join `test`.`t2`
+select * from t1, t2 full join t3 on t2.c=t3.e and t3.f=t1.a;
+ERROR 42S02: Table 'test.t3' doesn't exist
+select * from t1, t2 full outer join t3 on t2.c=t3.e and t3.f=t1.a;
+ERROR 42S02: Table 'test.t3' doesn't exist
+select * from t1, t2 natural full join t3;
+ERROR 42S02: Table 'test.t3' doesn't exist
+select * from t1, t2 natural full outer join t3;
+ERROR 42S02: Table 'test.t3' doesn't exist
 drop table t1, t2;
 # End of 12.3 tests

mysql-test/main/join.test

@@ -2055,21 +2055,79 @@ create table t1 (a int);
 insert into t1 (a) values (1),(2),(3);
 create table t2 (a int);
 insert into t2 (a) values (1),(2),(3);
-# This test only verifies syntax acceptance.
+# TODO fix PS protocol before end of FULL OUTER JOIN development
+--disable_ps_protocol
 --error ER_NOT_SUPPORTED_YET
 select * from t1 full join t2 on t1.a = t2.a;
+explain extended select * from t1 full join t2 on t1.a = t2.a;
+
 --error ER_NOT_SUPPORTED_YET
 select * from t1 full outer join t2 on t1.a = t2.a;
+explain extended select * from t1 full outer join t2 on t1.a = t2.a;
+
 --error ER_NOT_SUPPORTED_YET
 select * from t1 natural full outer join t2;
+explain extended select * from t1 natural full outer join t2;
+
 --error ER_NOT_SUPPORTED_YET
 select * from t1 natural full join t2;
+explain extended select * from t1 natural full join t2;
+
+create view v1 as select * from t1 full join t2 on t1.a = t2.a;
 --error ER_NOT_SUPPORTED_YET
+select * from v1;
+explain extended select * from v1;
+drop view v1;
+
 create view v1 as select * from t1 full outer join t2 on t1.a = t2.a;
 --error ER_NOT_SUPPORTED_YET
+select * from v1;
+explain extended select * from v1;
+drop view v1;
+
+create view v1 as select * from t1 natural full join t2;
+--error ER_NOT_SUPPORTED_YET
+select * from v1;
+explain extended select * from v1;
+drop view v1;
+
+create view v1 as select * from t1 natural full outer join t2;
+--error ER_NOT_SUPPORTED_YET
+select * from v1;
+explain extended select * from v1;
+drop view v1;
+
+--error ER_BAD_FIELD_ERROR
+select * from (select t1.a from t1 full join t2 on t1.a = t2.a union select * from t1) dt;
+
+--error ER_BAD_FIELD_ERROR
 select * from (select t1.a from t1 full outer join t2 on t1.a = t2.a union select * from t1) dt;
+
+--error ER_NOT_SUPPORTED_YET
+select * from (select t1.a from t1 natural full join t2 union select * from t1) dt;
+explain extended select * from (select t1.a from t1 natural full join t2 union select * from t1) dt;
+
+--error ER_NOT_SUPPORTED_YET
+select * from (select t1.a from t1 natural full outer join t2 union select * from t1) dt;
+explain extended select * from (select t1.a from t1 natural full outer join t2 union select * from t1) dt;
+
 --error ER_NOT_SUPPORTED_YET
 with cte as (select t1.a from t1 natural full join t2) select * from cte;
-drop table t1, t2;
+explain extended with cte as (select t1.a from t1 natural full join t2) select * from cte;
+
+--error ER_NO_SUCH_TABLE
+select * from t1, t2 full join t3 on t2.c=t3.e and t3.f=t1.a;
+
+--error ER_NO_SUCH_TABLE
+select * from t1, t2 full outer join t3 on t2.c=t3.e and t3.f=t1.a;
 
+--error ER_NO_SUCH_TABLE
+select * from t1, t2 natural full join t3;
+
+--error ER_NO_SUCH_TABLE
+select * from t1, t2 natural full outer join t3;
+
+drop table t1, t2;
+# TODO fix PS protocol before end of FULL OUTER JOIN development
+--enable_ps_protocol
 --echo # End of 12.3 tests

sql/sql_parse.cc

@@ -10305,11 +10305,6 @@ bool parse_sql(THD *thd, Parser_state *parser_state,
   bool mysql_parse_status= thd->variables.sql_mode & MODE_ORACLE
                            ? ORAparse(thd) : MYSQLparse(thd);
 
-  /* While we accept full join syntax, such joins are not yet supported. */
-  mysql_parse_status|= thd->lex->has_full_outer_join;
-  if (thd->lex->has_full_outer_join)
-    my_error(ER_NOT_SUPPORTED_YET, MYF(0), "full join");
-
   if (mysql_parse_status)
     /*
       Restore the original LEX if it was replaced when parsing

sql/sql_select.cc

@@ -1894,6 +1894,18 @@ JOIN::prepare(TABLE_LIST *tables_init, COND *conds_init, uint og_num,
     goto err;
   prepared= true;
 
+  /*
+    This check gates FULL JOIN functionality while it is under
+    development.  This check will be removed once FULL JOIN
+    has been completed and it allows some aspects of FULL JOIN
+    (see below) while exluding others, driven by whatever has
+    been implemented up to this point.
+  */
+  if (thd->lex->has_full_outer_join &&  // FULL JOIN not yet supported...
+      !thd->lex->is_view_context_analysis() &&  // ...but allow VIEW creation...
+      !thd->lex->describe)  // ...and limited EXPLAIN support during development
+    my_error(ER_NOT_SUPPORTED_YET, MYF(0), "full join");
+
   DBUG_RETURN(0); // All OK
 
 err:
@@ -2767,7 +2779,13 @@ JOIN::optimize_inner()
   with_two_phase_optimization= check_two_phase_optimization(thd);
   if (with_two_phase_optimization)
     optimization_state= JOIN::OPTIMIZATION_PHASE_1_DONE;
-  else
+  /*
+    Only during the FULL JOIN development cycle, disable second stage
+    optimization for FULL JOIN queries until the implementation is
+    mature enough to correctly execute the queries.  But for now
+    this allows for some EXPLAIN EXTENDED support.
+  */
+  else if (!thd->lex->has_full_outer_join)
   {
     if (optimize_stage2())
       DBUG_RETURN(1);
@@ -31710,8 +31728,13 @@ static void print_table_array(THD *thd,
       continue;
     }
 
-    /* JOIN_TYPE_OUTER is just a marker unrelated to real join */
-    if (curr->outer_join & (JOIN_TYPE_LEFT|JOIN_TYPE_RIGHT))
+    if (curr->outer_join & JOIN_TYPE_FULL)
+    {
+      if (curr->outer_join & JOIN_TYPE_NATURAL)
+        str->append(STRING_WITH_LEN(" natural"));
+      str->append(STRING_WITH_LEN(" full join "));
+    }
+    else if (curr->outer_join & (JOIN_TYPE_LEFT|JOIN_TYPE_RIGHT))
     {
       /* MySQL converts right to left joins */
       str->append(STRING_WITH_LEN(" left join "));
@@ -31722,9 +31745,15 @@ static void print_table_array(THD *thd,
       str->append(STRING_WITH_LEN(" semi join "));
     else
       str->append(STRING_WITH_LEN(" join "));
-    
+
     curr->print(thd, eliminated_tables, str, query_type);
-    if (curr->on_expr)
+    /*
+      NATURAL JOINs don't expose explicit join columns, so don't
+      print them as they're considered invalid syntax (this is
+      important for VIEWs as when VIEWs are loaded, their SQL
+      syntax is parsed again and must be valid).
+    */
+    if (curr->on_expr && !(curr->outer_join & JOIN_TYPE_NATURAL))
     {
       str->append(STRING_WITH_LEN(" on("));
       curr->on_expr->print(str, query_type);

sql/sql_view.cc

@@ -1909,6 +1909,7 @@ bool mysql_make_view(THD *thd, TABLE_SHARE *share, TABLE_LIST *view_table_alias,
   DBUG_ASSERT(view_query_lex == thd->lex);
   thd->lex= parent_query_lex;                            // Needed for prepare_security
   result= !view_table_alias->prelocking_placeholder && view_table_alias->prepare_security(thd);
+  parent_query_lex->has_full_outer_join|= view_query_lex->has_full_outer_join;
 
   lex_end(view_query_lex);
 end:

sql/sql_yacc.yy

@@ -12387,8 +12387,9 @@ join_table:
           }
           expr
           {
-            add_join_on(thd, $1, $8);
+            add_join_on(thd, $5, $8);
             $1->on_context= Lex->pop_context();
+            $5->on_context= $1->on_context;
             Select->parsing_place= NO_MATTER;
             $$= $1;
             Lex->has_full_outer_join= true;
@@ -12415,11 +12416,13 @@ join_table:
 
             Select->add_joined_table($1);
             $1->outer_join|= (JOIN_TYPE_LEFT |
-                              JOIN_TYPE_FULL);
+                              JOIN_TYPE_FULL |
+                              JOIN_TYPE_NATURAL);
 
             Select->add_joined_table($6);
             $6->outer_join|= (JOIN_TYPE_RIGHT |
-                              JOIN_TYPE_FULL);
+                              JOIN_TYPE_FULL |
+                              JOIN_TYPE_NATURAL);
 
             add_join_natural($6,$1,NULL,Select);
             Lex->has_full_outer_join= true;

sql/table.h

@@ -2212,10 +2212,11 @@ class IS_table_read_plan;
 #define VIEW_ALGORITHM_MERGE_FRM      1U
 #define VIEW_ALGORITHM_TMPTABLE_FRM   2U
 
-#define JOIN_TYPE_LEFT	1U
-#define JOIN_TYPE_RIGHT	2U
-#define JOIN_TYPE_FULL	4U
-#define JOIN_TYPE_OUTER 8U	/* Marker that this is an outer join */
+#define JOIN_TYPE_LEFT	  1U
+#define JOIN_TYPE_RIGHT	  2U
+#define JOIN_TYPE_FULL	  4U
+#define JOIN_TYPE_OUTER   8U	/* Marker that this is an outer join */
+#define JOIN_TYPE_NATURAL 16U
 
 /* view WITH CHECK OPTION parameter options */
 #define VIEW_CHECK_NONE       0