Natural join: the joined columns are not repeated any more when using SELECT *.

h2/src/main/org/h2/command/Parser.java

@@ -1252,8 +1252,10 @@ public class Parser {
                 for (int t = 0; t < tableCols.length; t++) {
                     String tableColumnName = tableCols[t].getName();
                     for (int j = 0; j < joinCols.length; j++) {
-                        String joinColumnName = joinCols[j].getName();
+                        Column c = joinCols[j];
+                        String joinColumnName = c.getName();
                         if (tableColumnName.equals(joinColumnName)) {
+                            join.addNaturalJoinColumn(c);
                             Expression tableExpr = new ExpressionColumn(database, tableSchema, last
                                     .getTableAlias(), tableColumnName);
                             Expression joinExpr = new ExpressionColumn(database, joinSchema, join

h2/src/main/org/h2/command/dml/Select.java

@@ -608,6 +608,9 @@ public class Select extends Query {
                 Column[] columns = t.getColumns();
                 for (int j = 0; j < columns.length; j++) {
                     Column c = columns[j];
+                    if (filter.isNaturalJoinColumn(c)) {
+                        continue;
+                    }
                     ExpressionColumn ec = new ExpressionColumn(session.getDatabase(), null, alias, c.getName());
                     expressions.add(i++, ec);
                 }

h2/src/main/org/h2/table/TableFilter.java

@@ -64,6 +64,7 @@ public class TableFilter implements ColumnResolver {
     private TableFilter join;
 
     private boolean outerJoin;
+    private ObjectArray naturalJoinColumns;
     private boolean foundOne;
     private Expression fullCondition;
 
@@ -726,4 +727,26 @@ public class TableFilter implements ColumnResolver {
         return alias != null ? alias : "" + table;
     }
 
+    /**
+     * Add a column to the natural join key column list.
+     *
+     * @param c the column to add
+     */
+    public void addNaturalJoinColumn(Column c) {
+        if (naturalJoinColumns == null) {
+            naturalJoinColumns = new ObjectArray();
+        }
+        naturalJoinColumns.add(c);
+    }
+
+    /**
+     * Check if the given column is a natural join column.
+     *
+     * @param c the column to check
+     * @return true if this is a joined natural join column
+     */
+    public boolean isNaturalJoinColumn(Column c) {
+        return naturalJoinColumns != null && naturalJoinColumns.indexOf(c) >= 0;
+    }
+
 }

h2/src/test/org/h2/test/test-1.1.txt

@@ -2706,9 +2706,9 @@ select * from two;
 select * from one natural join two left join two three on
 one.id=three.id left join one four on two.id=four.id where three.val
 is null;
-> ID ID VAL  ID VAL  ID
-> -- -- ---- -- ---- --
-> 0  0  null 0  null 0
+> ID VAL  ID VAL  ID
+> -- ---- -- ---- --
+> 0  null 0  null 0
 > rows: 1
 
 -- Query #2: should return one row
@@ -2716,27 +2716,27 @@ is null;
 select * from one natural join two left join two three on
 one.id=three.id left join one four on two.id=four.id where
 three.val>=DATE'2006-07-01';
-> ID ID VAL        ID VAL        ID
-> -- -- ---------- -- ---------- --
-> 2  2  2006-07-01 2  2006-07-01 2
+> ID VAL        ID VAL        ID
+> -- ---------- -- ---------- --
+> 2  2006-07-01 2  2006-07-01 2
 > rows: 1
 
 -- Query #3: should return the union of #1 and #2
 select * from one natural join two left join two three on
 one.id=three.id left join one four on two.id=four.id where three.val
 is null or three.val>=DATE'2006-07-01';
-> ID ID VAL        ID VAL        ID
-> -- -- ---------- -- ---------- --
-> 0  0  null       0  null       0
-> 2  2  2006-07-01 2  2006-07-01 2
+> ID VAL        ID VAL        ID
+> -- ---------- -- ---------- --
+> 0  null       0  null       0
+> 2  2006-07-01 2  2006-07-01 2
 > rows: 2
 
 explain select * from one natural join two left join two three on
 one.id=three.id left join one four on two.id=four.id where three.val
 is null or three.val>=DATE'2006-07-01';
 > PLAN
-> -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT ONE.ID, TWO.ID, TWO.VAL, THREE.ID, THREE.VAL, FOUR.ID FROM PUBLIC.ONE /* PUBLIC.ONE_TABLE_SCAN */ INNER JOIN PUBLIC.TWO /* PUBLIC.PRIMARY_KEY_14: ID = PUBLIC.ONE.ID AND ID = PUBLIC.ONE.ID */ ON 1=1 /* WHERE PUBLIC.ONE.ID = PUBLIC.TWO.ID */ LEFT OUTER JOIN PUBLIC.TWO THREE /* PUBLIC.PRIMARY_KEY_14: ID = ONE.ID */ ON ONE.ID = THREE.ID LEFT OUTER JOIN PUBLIC.ONE FOUR /* PUBLIC.PRIMARY_KEY_1: ID = TWO.ID */ ON TWO.ID = FOUR.ID WHERE (PUBLIC.ONE.ID = PUBLIC.TWO.ID) AND ((THREE.VAL IS NULL) OR (THREE.VAL >= DATE '2006-07-01'))
+> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT ONE.ID, TWO.VAL, THREE.ID, THREE.VAL, FOUR.ID FROM PUBLIC.ONE /* PUBLIC.ONE_TABLE_SCAN */ INNER JOIN PUBLIC.TWO /* PUBLIC.PRIMARY_KEY_14: ID = PUBLIC.ONE.ID AND ID = PUBLIC.ONE.ID */ ON 1=1 /* WHERE PUBLIC.ONE.ID = PUBLIC.TWO.ID */ LEFT OUTER JOIN PUBLIC.TWO THREE /* PUBLIC.PRIMARY_KEY_14: ID = ONE.ID */ ON ONE.ID = THREE.ID LEFT OUTER JOIN PUBLIC.ONE FOUR /* PUBLIC.PRIMARY_KEY_1: ID = TWO.ID */ ON TWO.ID = FOUR.ID WHERE (PUBLIC.ONE.ID = PUBLIC.TWO.ID) AND ((THREE.VAL IS NULL) OR (THREE.VAL >= DATE '2006-07-01'))
 > rows: 1
 
 -- Query #4: same as #3, but the joins have been manually re-ordered
@@ -2744,10 +2744,10 @@ is null or three.val>=DATE'2006-07-01';
 select * from one natural join two left join one four on
 two.id=four.id left join two three on one.id=three.id where three.val
 is null or three.val>=DATE'2006-07-01';
-> ID ID VAL        ID ID VAL
-> -- -- ---------- -- -- ----------
-> 0  0  null       0  0  null
-> 2  2  2006-07-01 2  2  2006-07-01
+> ID VAL        ID ID VAL
+> -- ---------- -- -- ----------
+> 0  null       0  0  null
+> 2  2006-07-01 2  2  2006-07-01
 > rows: 2
 
 drop table one;
@@ -3659,9 +3659,9 @@ select * from left_hand left join right_hand on left_hand.id=right_hand.id;
 
 -- h2: 1 (2 cols); postgresql, mysql: 1 (1 col); derby, hsqldb: no natural join
 select * from left_hand natural join right_hand;
-> ID ID
-> -- --
-> 0  0
+> ID
+> --
+> 0
 > rows: 1
 
 -- h2, postgresql, mysql, derby, hsqldb: 1
@@ -3680,8 +3680,8 @@ select * from left_hand left join right_hand on left_hand.id=right_hand.id where
 
 -- h2: 0 (2 cols); postgresql, mysql: 0 (1 col); derby, hsqldb: no natural join
 select * from left_hand natural join right_hand where left_hand.id=1;
-> ID ID
-> -- --
+> ID
+> --
 > rows: 0
 
 -- !!! h2: 1; postgresql, mysql, hsqldb: 0; derby: exception
@@ -3714,8 +3714,8 @@ select * from left_hand left join right_hand on left_hand.id=right_hand.id where
 
 -- h2: 0 rows; postgresql, mysql: exception; derby, hsqldb: no natural join
 select * from left_hand natural join right_hand where left_hand.id=1 group by left_hand.id having right_hand.id=2;
-> ID ID
-> -- --
+> ID
+> --
 > rows: 0
 
 drop table right_hand;
@@ -6141,14 +6141,14 @@ select * from t1 cross join t2;
 > rows: 4
 
 select * from t1 natural join t2;
-> ID NAME ID NAME
-> -- ---- -- ----
+> ID NAME
+> -- ----
 > rows: 0
 
 explain select * from t1 natural join t2;
 > PLAN
-> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT T1.ID, T1.NAME, T2.ID, T2.NAME FROM PUBLIC.T1 /* PUBLIC.T1_TABLE_SCAN */ INNER JOIN PUBLIC.T2 /* PUBLIC.T2_TABLE_SCAN */ ON 1=1 WHERE (PUBLIC.T1.ID = PUBLIC.T2.ID) AND (PUBLIC.T1.NAME = PUBLIC.T2.NAME)
+> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT T1.ID, T1.NAME FROM PUBLIC.T1 /* PUBLIC.T1_TABLE_SCAN */ INNER JOIN PUBLIC.T2 /* PUBLIC.T2_TABLE_SCAN */ ON 1=1 WHERE (PUBLIC.T1.ID = PUBLIC.T2.ID) AND (PUBLIC.T1.NAME = PUBLIC.T2.NAME)
 > rows: 1
 
 drop table t1;
@@ -6176,16 +6176,16 @@ insert into INVOICE_LINE values(10, 1, 0, 'Super Soap'), (20, 1, 0, 'Regular Soa
 > update count: 2
 
 select c.*, i.*, l.* from customer c natural join invoice i natural join INVOICE_LINE l;
-> CUSTOMERID CUSTOMER_NAME CUSTOMERID INVOICEID INVOICE_TEXT LINE_ID INVOICEID CUSTOMERID LINE_TEXT
-> ---------- ------------- ---------- --------- ------------ ------- --------- ---------- ------------
-> 0          Acme          0          1         Soap         10      1         0          Super Soap
-> 0          Acme          0          1         Soap         20      1         0          Regular Soap
+> CUSTOMERID CUSTOMER_NAME INVOICEID INVOICE_TEXT LINE_ID LINE_TEXT
+> ---------- ------------- --------- ------------ ------- ------------
+> 0          Acme          1         Soap         10      Super Soap
+> 0          Acme          1         Soap         20      Regular Soap
 > rows: 2
 
 explain select c.*, i.*, l.* from customer c natural join invoice i natural join INVOICE_LINE l;
 > PLAN
-> --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT C.CUSTOMERID, C.CUSTOMER_NAME, I.CUSTOMERID, I.INVOICEID, I.INVOICE_TEXT, L.LINE_ID, L.INVOICEID, L.CUSTOMERID, L.LINE_TEXT FROM PUBLIC.CUSTOMER C /* PUBLIC.CUSTOMER_TABLE_SCAN */ INNER JOIN PUBLIC.INVOICE I /* PUBLIC.INVOICE_TABLE_SCAN */ ON 1=1 /* WHERE PUBLIC.C.CUSTOMERID = PUBLIC.I.CUSTOMERID */ INNER JOIN PUBLIC.INVOICE_LINE L /* PUBLIC.INVOICE_LINE_TABLE_SCAN */ ON 1=1 WHERE (PUBLIC.C.CUSTOMERID = PUBLIC.I.CUSTOMERID) AND ((PUBLIC.I.CUSTOMERID = PUBLIC.L.CUSTOMERID) AND (PUBLIC.I.INVOICEID = PUBLIC.L.INVOICEID))
+> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT C.CUSTOMERID, C.CUSTOMER_NAME, I.INVOICEID, I.INVOICE_TEXT, L.LINE_ID, L.LINE_TEXT FROM PUBLIC.CUSTOMER C /* PUBLIC.CUSTOMER_TABLE_SCAN */ INNER JOIN PUBLIC.INVOICE I /* PUBLIC.INVOICE_TABLE_SCAN */ ON 1=1 /* WHERE PUBLIC.C.CUSTOMERID = PUBLIC.I.CUSTOMERID */ INNER JOIN PUBLIC.INVOICE_LINE L /* PUBLIC.INVOICE_LINE_TABLE_SCAN */ ON 1=1 WHERE (PUBLIC.C.CUSTOMERID = PUBLIC.I.CUSTOMERID) AND ((PUBLIC.I.CUSTOMERID = PUBLIC.L.CUSTOMERID) AND (PUBLIC.I.INVOICEID = PUBLIC.L.INVOICEID))
 > rows: 1
 
 drop table customer;