correct support for a mix of UNION/UNION ALL in the same query.

Bug#1428

mysql-test/r/union.result

@@ -36,8 +36,6 @@ a	b
 1	a
 2	b
 3	c
-3	c
-3	c
 4	d
 5	f
 6	e
@@ -48,8 +46,6 @@ select 0,'#' union select a,b from t1 union all select a,b from t2 union select
 1	a
 2	b
 3	c
-3	c
-3	c
 4	d
 5	f
 6	e
@@ -920,5 +916,9 @@ select * from t1 UNION select * from t1 UNION ALL select * from t1;
 i
 1
 1
-1
 drop table t1;
+select 1 as a union all select 1 union all select 2 union select 1 union all select 2;
+a
+1
+2
+2

mysql-test/t/union.test

@@ -493,6 +493,7 @@ create table t1 (i int);
 insert into t1 values (1);
 select * from t1 UNION select * from t1;
 select * from t1 UNION ALL select * from t1;
-# The following should return 2 lines
 select * from t1 UNION select * from t1 UNION ALL select * from t1;
 drop table t1;
+select 1 as a union all select 1 union all select 2 union select 1 union all select 2;
+

sql/mysql_priv.h

@@ -210,9 +210,6 @@ extern CHARSET_INFO *national_charset_info, *table_alias_charset;
 #define OPTION_RELAXED_UNIQUE_CHECKS    (1L << 27)
 #define SELECT_NO_UNLOCK                (1L << 28)
 
-/* options for UNION set by the yacc parser (stored in unit->union_option) */
-#define UNION_ALL               1
-
 /* Bits for different SQL modes modes (including ANSI mode) */
 #define MODE_REAL_AS_FLOAT      	1
 #define MODE_PIPES_AS_CONCAT    	2

sql/sql_derived.cc

@@ -138,7 +138,7 @@ static int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit,
   */
   if (!(table= create_tmp_table(thd, &derived_result->tmp_table_param,
 				unit->types, (ORDER*) 0, 
-				is_union && !unit->union_option, 1,
+				is_union && unit->union_distinct, 1,
 				(first_select->options | thd->options |
 				 TMP_TABLE_ALL_COLUMNS),
 				HA_POS_ERROR,

sql/sql_lex.cc

@@ -997,7 +997,7 @@ void st_select_lex_unit::init_query()
   global_parameters= first_select();
   select_limit_cnt= HA_POS_ERROR;
   offset_limit_cnt= 0;
-  union_option= 0;
+  union_distinct= 0;
   prepared= optimized= executed= 0;
   item= 0;
   union_result= 0;
@@ -1572,7 +1572,7 @@ void st_select_lex_unit::print(String *str)
     if (sl != first_select())
     {
       str->append(" union ", 7);
-      if (union_option & UNION_ALL)
+      if (!union_distinct)
 	str->append("all ", 4);
     }
     if (sl->braces)

sql/sql_lex.h

@@ -335,7 +335,7 @@ class st_select_lex_unit: public st_select_lex_node {
   /* fake SELECT_LEX for union processing */
   st_select_lex *fake_select_lex;
 
-  uint union_option;
+  st_select_lex *union_distinct; /* pointer to the last UNION DISTINCT */
 
   void init_query();
   bool create_total_list(THD *thd, st_lex *lex, TABLE_LIST **result);

sql/sql_union.cc

@@ -210,7 +210,7 @@ int st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
     union_result->tmp_table_param.field_count= types.elements;
     if (!(table= create_tmp_table(thd_arg,
 				  &union_result->tmp_table_param, types,
-				  (ORDER*) 0, !union_option, 1, 
+				  (ORDER*) 0, union_distinct, 1, 
 				  (first_select_in_union()->options |
 				   thd_arg->options |
 				   TMP_TABLE_ALL_COLUMNS),
@@ -267,6 +267,8 @@ int st_select_lex_unit::exec()
       item->reset();
       table->file->delete_all_rows();
     }
+    if (union_distinct) // for subselects
+      table->file->extra(HA_EXTRA_CHANGE_KEY_TO_UNIQUE);
     for (SELECT_LEX *sl= select_cursor; sl; sl= sl->next_select())
     {
       ha_rows records_at_start= 0;
@@ -317,6 +319,8 @@ int st_select_lex_unit::exec()
       {
 	records_at_start= table->file->records;
 	sl->join->exec();
+        if (sl == union_distinct)
+          table->file->extra(HA_EXTRA_CHANGE_KEY_TO_DUP);
 	res= sl->join->error;
 	offset_limit_cnt= sl->offset_limit;
 	if (!res && union_result->flush())

sql/sql_yacc.yy

@@ -611,7 +611,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 	udf_type if_exists opt_local opt_table_options table_options
         table_option opt_if_not_exists opt_no_write_to_binlog opt_var_type
         opt_var_ident_type delete_option opt_temporary all_or_any opt_distinct
-        opt_ignore_leaves fulltext_options spatial_type
+        opt_ignore_leaves fulltext_options spatial_type union_option
 
 %type <ulong_num>
 	ULONG_NUM raid_types merge_insert_types
@@ -718,7 +718,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 	table_to_table_list table_to_table opt_table_list opt_as
 	handler_rkey_function handler_read_or_scan
 	single_multi table_wild_list table_wild_one opt_wild
-	union_clause union_list union_option
+	union_clause union_list
 	precision subselect_start opt_and charset
 	subselect_end select_var_list select_var_list_init help opt_len
 	opt_extended_describe
@@ -5589,6 +5589,9 @@ union_list:
 	    YYABORT;
           mysql_init_select(lex);
 	  lex->current_select->linkage=UNION_TYPE;
+          if ($2) /* UNION DISTINCT - remember position */
+            lex->current_select->master_unit()->union_distinct=
+                                                      lex->current_select;
 	}
 	select_init {}
 	;
@@ -5630,9 +5633,10 @@ order_or_limit:
 	;
 
 union_option:
-	/* empty */ {}
-	| DISTINCT {}
-	| ALL {Select->master_unit()->union_option|= UNION_ALL;};
+	/* empty */ { $$=1; }
+	| DISTINCT  { $$=1; }
+	| ALL       { $$=0; }
+        ;
 
 singlerow_subselect:
 	subselect_start singlerow_subselect_init