MDEV-29919: Support INSERT ... AS alias ON DUPLICATE KEY UPDATE

mysql-test/main/insert_update_alias.result

@@ -0,0 +1,95 @@
+#
+# MDEV-29919: Support INSERT ... VALUES AS alias ON DUPLICATE KEY UPDATE
+#
+#
+# Test setup
+#
+CREATE TABLE t1 (
+a INT PRIMARY KEY,
+b INT,
+c INT
+);
+#
+# Basic INSERT AS alias ON DUPLICATE KEY UPDATE
+#
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 20, 200) AS new
+ON DUPLICATE KEY UPDATE b = new.b, c = new.c;
+SELECT * FROM t1;
+a	b	c
+1	20	200
+#
+# Multiple rows with AS alias
+#
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 20, 200), (2, 30, 300) AS new
+ON DUPLICATE KEY UPDATE b = new.b;
+SELECT * FROM t1 ORDER BY a;
+a	b	c
+1	20	100
+2	30	300
+#
+# Expression using alias columns
+#
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 5, 50) AS new
+ON DUPLICATE KEY UPDATE b = new.b + new.c, c = new.a * 10;
+SELECT * FROM t1;
+a	b	c
+1	55	10
+#
+# Mix of alias and table column references
+#
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 20, 200) AS new
+ON DUPLICATE KEY UPDATE b = new.b, c = t1.c + new.c;
+SELECT * FROM t1;
+a	b	c
+1	20	300
+#
+# INSERT without ON DUPLICATE KEY (alias should be ignored)
+#
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100) AS new;
+SELECT * FROM t1;
+a	b	c
+1	10	100
+#
+# Different alias names
+#
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 99, 999) AS inserted_row
+ON DUPLICATE KEY UPDATE b = inserted_row.b, c = inserted_row.c;
+SELECT * FROM t1;
+a	b	c
+1	99	999
+#
+# Alias cannot be the same as the target table name
+#
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 50, 500) AS t1
+ON DUPLICATE KEY UPDATE b = t1.b;
+ERROR 42000: Not unique table/alias: 't1'
+#
+# Verify that AS alias is NOT allowed in REPLACE
+#
+REPLACE INTO t1 VALUES (1, 50, 500) AS new;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use
+#
+# Verify that AS alias is NOT allowed in CREATE ... VALUES
+#
+CREATE TABLE t2 AS VALUES (1, 10, 100) AS new;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use
+#
+# Cleanup
+#
+DROP TABLE t1;
+DROP TABLE IF EXISTS t2;
+#
+# End of tests
+#

mysql-test/main/insert_update_alias.test

@@ -0,0 +1,101 @@
+--echo #
+--echo # MDEV-29919: Support INSERT ... VALUES AS alias ON DUPLICATE KEY UPDATE
+--echo #
+
+#
+# This test validates the row alias syntax for INSERT ON DUPLICATE KEY UPDATE
+# which allows referencing inserted values using alias.column instead of VALUES(column)
+#
+
+--echo #
+--echo # Test setup
+--echo #
+CREATE TABLE t1 (
+  a INT PRIMARY KEY,
+  b INT,
+  c INT
+);
+
+--echo #
+--echo # Basic INSERT AS alias ON DUPLICATE KEY UPDATE
+--echo #
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 20, 200) AS new
+  ON DUPLICATE KEY UPDATE b = new.b, c = new.c;
+SELECT * FROM t1;
+
+--echo #
+--echo # Multiple rows with AS alias
+--echo #
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 20, 200), (2, 30, 300) AS new
+  ON DUPLICATE KEY UPDATE b = new.b;
+SELECT * FROM t1 ORDER BY a;
+
+--echo #
+--echo # Expression using alias columns
+--echo #
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 5, 50) AS new
+  ON DUPLICATE KEY UPDATE b = new.b + new.c, c = new.a * 10;
+SELECT * FROM t1;
+
+--echo #
+--echo # Mix of alias and table column references
+--echo #
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 20, 200) AS new
+  ON DUPLICATE KEY UPDATE b = new.b, c = t1.c + new.c;
+SELECT * FROM t1;
+
+--echo #
+--echo # INSERT without ON DUPLICATE KEY (alias should be ignored)
+--echo #
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100) AS new;
+SELECT * FROM t1;
+
+--echo #
+--echo # Different alias names
+--echo #
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100);
+INSERT INTO t1 VALUES (1, 99, 999) AS inserted_row
+  ON DUPLICATE KEY UPDATE b = inserted_row.b, c = inserted_row.c;
+SELECT * FROM t1;
+
+--echo #
+--echo # Alias cannot be the same as the target table name
+--echo #
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (1, 10, 100);
+--error ER_NONUNIQ_TABLE
+INSERT INTO t1 VALUES (1, 50, 500) AS t1
+  ON DUPLICATE KEY UPDATE b = t1.b;
+
+--echo #
+--echo # Verify that AS alias is NOT allowed in REPLACE
+--echo #
+--error ER_SYNTAX_ERROR
+REPLACE INTO t1 VALUES (1, 50, 500) AS new;
+
+--echo #
+--echo # Verify that AS alias is NOT allowed in CREATE ... VALUES
+--echo #
+--error ER_SYNTAX_ERROR
+CREATE TABLE t2 AS VALUES (1, 10, 100) AS new;
+
+--echo #
+--echo # Cleanup
+--echo #
+DROP TABLE t1;
+--disable_warnings
+DROP TABLE IF EXISTS t2;
+--enable_warnings
+
+--echo #
+--echo # End of tests
+--echo #

sql/item.cc

@@ -6433,6 +6433,23 @@ bool Item_field::fix_fields(THD *thd, Item **reference)
   if (!field)					// If field is not checked
   {
     TABLE_LIST *table_list;
+
+    /* Handle INSERT ... VALUES (...) AS alias ON DUPLICATE KEY UPDATE */
+    if (table_name.str &&
+        table_name.streq(thd->lex->insert_values_alias))
+    {
+      DBUG_ASSERT(thd->lex->duplicates == DUP_UPDATE);
+      Item_field *field_ref= new (thd->mem_root)
+        Item_field(thd, context, db_name, Lex_cstring_strlen(NULL), field_name);
+      if (!field_ref)
+        return TRUE;
+      Item_insert_value *ins_val= new (thd->mem_root)
+        Item_insert_value(thd, context, field_ref);
+      if (!ins_val)
+        return TRUE;
+      thd->change_item_tree(reference, ins_val);
+      return ins_val->fix_fields(thd, reference);
+    }
     /*
       In case of view, find_field_in_tables() write pointer to view field
       expression to 'reference', i.e. it substitute that expression instead

sql/sql_insert.cc

@@ -1825,6 +1825,17 @@ int mysql_prepare_insert(THD *thd, TABLE_LIST *table_list,
 
   if (duplic == DUP_UPDATE)
   {
+    /*
+      The row alias for INSERT ... AS alias cannot be the same as the
+      target table name, as this would make column references ambiguous.
+    */
+    if (thd->lex->insert_values_alias.str &&
+        table_list->table_name.streq(thd->lex->insert_values_alias))
+    {
+      my_error(ER_NONUNIQ_TABLE, MYF(0), thd->lex->insert_values_alias.str);
+      DBUG_RETURN(1);
+    }
+
     /* it should be allocated before Item::fix_fields() */
     if (table_list->set_insert_values(thd->mem_root))
       DBUG_RETURN(1);

sql/sql_lex.cc

@@ -1277,6 +1277,7 @@ void LEX::start(THD *thd_arg)
   part_info= 0;
   m_sql_cmd= NULL;
   duplicates= DUP_ERROR;
+  insert_values_alias= Lex_ident_sys();
   spname= NULL;
   spcont= NULL;
   proc_list.first= 0;

sql/sql_lex.h

@@ -3454,6 +3454,8 @@ struct LEX: public Query_tables_list
   const char *clause_that_disallows_subselect;
 
   enum enum_duplicates duplicates;
+  /* Represents INSERT...VALUES as <alias> */
+  Lex_ident_sys_st insert_values_alias;
   enum enum_tx_isolation tx_isolation;
   enum enum_ha_read_modes ha_read_mode;
   union {

sql/sql_yacc.yy

@@ -9035,13 +9035,32 @@ table_value_constructor:
             if (Lex->parsed_TVC_start())
               MYSQL_YYABORT;
 	  }
-	  values_list
+	  values_list opt_values_row_alias
 	  {
             if (!($$= Lex->parsed_TVC_end()))
 	      MYSQL_YYABORT;
 	  }
 	;
 
+/*
+  Optional alias for the row(s) being inserted.
+  Syntax: INSERT ... VALUES (...) AS alias
+  Used to reference new values in ON DUPLICATE KEY UPDATE clause.
+*/
+opt_values_row_alias:
+          {
+            Lex->insert_values_alias= Lex_ident_sys();
+          }
+        | AS ident
+          {
+            if (Lex->sql_command == SQLCOM_REPLACE || Lex->sql_command == SQLCOM_CREATE_TABLE)
+            {
+                my_yyabort_error((ER_SYNTAX_ERROR, MYF(0)));
+            }
+            Lex->insert_values_alias= $2;
+          }
+        ;
+
 opt_hint_comment:
           /*empty */   { $$.init(); }
         | HINT_COMMENT { $$= $1; }