CREATE TABLE AS WITH NO DATA - Mailing list pgsql-hackers

Another small piece of parser acrobatics to become standard conforming.
? src/backend/parser/gram.output
Index: doc/src/sgml/ref/create_table_as.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/ref/create_table_as.sgml,v
retrieving revision 1.37
diff -u -3 -p -c -r1.37 create_table_as.sgml
*** doc/src/sgml/ref/create_table_as.sgml    3 Jun 2007 17:06:12 -0000    1.37
--- doc/src/sgml/ref/create_table_as.sgml    27 Oct 2008 16:54:29 -0000
*************** CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY
*** 26,31 ****
--- 26,32 ----
      [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
      [ TABLESPACE <replaceable class="PARAMETER">tablespace</replaceable> ]
      AS <replaceable>query</replaceable>
+     [ WITH [ NO ] DATA ]
  </synopsis>
   </refsynopsisdiv>

*************** CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY
*** 201,206 ****
--- 202,219 ----
       </para>
      </listitem>
     </varlistentry>
+
+    <varlistentry>
+     <term><literal>WITH [ NO ] DATA</></term>
+     <listitem>
+      <para>
+       This clause specifies whether or not the data produced by the query
+       should be copied into the new table.  If not, only the table structure
+       is copied.  The default is to copy the data.
+      </para>
+     </listitem>
+    </varlistentry>
+
    </variablelist>
   </refsect1>

*************** CREATE TEMP TABLE films_recent WITH (OID
*** 265,271 ****

    <para>
     <command>CREATE TABLE AS</command> conforms to the <acronym>SQL</acronym>
!    standard, with the following exceptions:

     <itemizedlist spacing="compact">
      <listitem>
--- 278,284 ----

    <para>
     <command>CREATE TABLE AS</command> conforms to the <acronym>SQL</acronym>
!    standard.  The following are nonstandard extensions:

     <itemizedlist spacing="compact">
      <listitem>
*************** CREATE TEMP TABLE films_recent WITH (OID
*** 278,289 ****

      <listitem>
       <para>
!       The standard defines a <literal>WITH [ NO ] DATA</literal> clause;
!       this is not currently implemented by <productname>PostgreSQL</>.
!       The behavior provided by <productname>PostgreSQL</> is equivalent
!       to the standard's <literal>WITH DATA</literal> case.
!       <literal>WITH NO DATA</literal> can be simulated by appending
!       <literal>LIMIT 0</> to the query.
       </para>
      </listitem>

--- 291,298 ----

      <listitem>
       <para>
!       In the standard, the <literal>WITH [ NO ] DATA</literal> clause
!       is required; in PostgreSQL it is optional.
       </para>
      </listitem>

Index: src/backend/parser/gram.y
===================================================================
RCS file: /cvsroot/pgsql/src/backend/parser/gram.y,v
retrieving revision 2.628
diff -u -3 -p -c -r2.628 gram.y
*** src/backend/parser/gram.y    22 Oct 2008 11:00:34 -0000    2.628
--- src/backend/parser/gram.y    27 Oct 2008 16:54:29 -0000
*************** static TypeName *TableFuncTypeName(List
*** 216,222 ****
  %type <ival>    opt_lock lock_type cast_context
  %type <boolean>    opt_force opt_or_replace
                  opt_grant_grant_option opt_grant_admin_option
!                 opt_nowait opt_if_exists

  %type <list>    OptRoleList
  %type <defelt>    OptRoleElem
--- 216,222 ----
  %type <ival>    opt_lock lock_type cast_context
  %type <boolean>    opt_force opt_or_replace
                  opt_grant_grant_option opt_grant_admin_option
!                 opt_nowait opt_if_exists opt_with_data

  %type <list>    OptRoleList
  %type <defelt>    OptRoleElem
*************** static TypeName *TableFuncTypeName(List
*** 484,490 ****
   * list and so can never be entered directly.  The filter in parser.c
   * creates these tokens when required.
   */
! %token            NULLS_FIRST NULLS_LAST WITH_CASCADED WITH_LOCAL WITH_CHECK

  /* Special token types, not actually keywords - see the "lex" file */
  %token <str>    IDENT FCONST SCONST BCONST XCONST Op
--- 484,490 ----
   * list and so can never be entered directly.  The filter in parser.c
   * creates these tokens when required.
   */
! %token            NULLS_FIRST NULLS_LAST WITH_CASCADED WITH_CHECK WITH_DATA WITH_LOCAL WITH_NO

  /* Special token types, not actually keywords - see the "lex" file */
  %token <str>    IDENT FCONST SCONST BCONST XCONST Op
*************** OptConsTableSpace:   USING INDEX TABLESP
*** 2399,2405 ****
   */

  CreateAsStmt:
!         CREATE OptTemp TABLE create_as_target AS SelectStmt
                  {
                      /*
                       * When the SelectStmt is a set-operation tree, we must
--- 2399,2405 ----
   */

  CreateAsStmt:
!         CREATE OptTemp TABLE create_as_target AS SelectStmt opt_with_data
                  {
                      /*
                       * When the SelectStmt is a set-operation tree, we must
*************** CreateAsStmt:
*** 2416,2421 ****
--- 2416,2423 ----
                                   scanner_errposition(exprLocation((Node *) n->intoClause))));
                      $4->rel->istemp = $2;
                      n->intoClause = $4;
+                     if (!$7)
+                         ((SelectStmt *)$6)->limitCount = makeIntConst(0, -1);
                      $$ = $6;
                  }
          ;
*************** CreateAsElement:
*** 2458,2463 ****
--- 2460,2471 ----
                  }
          ;

+ opt_with_data:
+             WITH_DATA                                { $$ = TRUE; }
+             | WITH_NO DATA_P                            { $$ = FALSE; }
+             | /*EMPTY*/                                { $$ = TRUE; }
+         ;
+

  /*****************************************************************************
   *
Index: src/backend/parser/parser.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/parser/parser.c,v
retrieving revision 1.74
diff -u -3 -p -c -r1.74 parser.c
*** src/backend/parser/parser.c    29 Aug 2008 13:02:32 -0000    1.74
--- src/backend/parser/parser.c    27 Oct 2008 16:54:29 -0000
*************** filtered_base_yylex(void)
*** 129,142 ****
          case WITH:

              /*
!              * WITH CASCADED, LOCAL, or CHECK must be reduced to one token
               *
               * XXX an alternative way is to recognize just WITH_TIME and put
               * the ugliness into the datetime datatype productions instead of
               * WITH CHECK OPTION.  However that requires promoting WITH to a
!              * fully reserved word.  If we ever have to do that anyway
!              * (perhaps for SQL99 recursive queries), come back and simplify
!              * this code.
               */
              cur_yylval = base_yylval;
              cur_yylloc = base_yylloc;
--- 129,141 ----
          case WITH:

              /*
!              * WITH CASCADED, DATA, LOCAL, or CHECK must be reduced to one token
               *
               * XXX an alternative way is to recognize just WITH_TIME and put
               * the ugliness into the datetime datatype productions instead of
               * WITH CHECK OPTION.  However that requires promoting WITH to a
!              * fully reserved word.  If we ever have to do that anyway,
!              * come back and simplify this code.
               */
              cur_yylval = base_yylval;
              cur_yylloc = base_yylloc;
*************** filtered_base_yylex(void)
*** 146,156 ****
                  case CASCADED:
                      cur_token = WITH_CASCADED;
                      break;
                  case LOCAL:
                      cur_token = WITH_LOCAL;
                      break;
!                 case CHECK:
!                     cur_token = WITH_CHECK;
                      break;
                  default:
                      /* save the lookahead token for next time */
--- 145,161 ----
                  case CASCADED:
                      cur_token = WITH_CASCADED;
                      break;
+                 case CHECK:
+                     cur_token = WITH_CHECK;
+                     break;
+                 case DATA_P:
+                     cur_token = WITH_DATA;
+                     break;
                  case LOCAL:
                      cur_token = WITH_LOCAL;
                      break;
!                 case NO:
!                     cur_token = WITH_NO;
                      break;
                  default:
                      /* save the lookahead token for next time */