Parse T-SQL and Snowflake multi-item ADD lists

src/main/java/net/sf/jsqlparser/statement/alter/AlterExpression.java

@@ -90,6 +90,9 @@ public enum TableRenameKeyword {
 
     private boolean useBrackets = false;
 
+    // T-SQL/Snowflake ADD lists items comma-separated, without brackets.
+    private boolean bareAddList = false;
+
     private boolean useIfNotExists = false;
 
     private String partitionType;
@@ -137,6 +140,14 @@ public void useBrackets(boolean useBrackets) {
         this.useBrackets = useBrackets;
     }
 
+    public boolean isBareAddList() {
+        return bareAddList;
+    }
+
+    public void setBareAddList(boolean bareAddList) {
+        this.bareAddList = bareAddList;
+    }
+
     public void hasColumn(boolean hasColumn) {
         this.hasColumn = hasColumn;
     }
@@ -1638,7 +1649,7 @@ private void toStringGeneral(StringBuilder b, Consumer<ColumnDataType> columnPri
                     b.append(optionalSpecifier).append(" ");
                 }
                 b.append(columnOldName).append(" ");
-            } else if (colDataTypeList.size() > 1) {
+            } else if (colDataTypeList.size() > 1 && !bareAddList) {
                 b.append("(");
             } else {
                 if (hasColumn) {
@@ -1664,9 +1675,14 @@ private void toStringGeneral(StringBuilder b, Consumer<ColumnDataType> columnPri
             if (useBrackets && colDataTypeList.size() == 1) {
                 b.append(')');
             }
-            if (colDataTypeList.size() > 1) {
+            if (colDataTypeList.size() > 1 && !bareAddList) {
                 b.append(")");
             }
+            if (constraint != null && bareAddList) {
+                // T-SQL/Snowflake ADD lists may append a table constraint after
+                // the column definitions.
+                b.append(", ").append(constraint);
+            }
         } else if (getColumnSetNotNullList() != null) {
             b.append("COLUMN ");
             b.append(PlainSelect.getStringList(columnSetNotNullList));

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -2462,6 +2462,38 @@ public class CCJSqlParser extends AbstractJSqlParser<CCJSqlParser> {
         }
     }
 
+    /**
+     * True when the item after a comma inside a T-SQL/Snowflake ADD list is
+     * another column definition or table constraint rather than the start of a
+     * new alter action, which the enclosing productions handle.
+     */
+    private boolean isAlterAddListItemAhead() {
+        switch (getToken(1).kind) {
+            case K_CONSTRAINT:
+            case K_CHECK:
+            case K_PRIMARY:
+            case K_UNIQUE:
+            case K_FOREIGN:
+                return true;
+            case K_ADD:
+            case K_ALTER:
+            case K_CHANGE:
+            case K_MODIFY:
+            case K_DROP:
+            case K_FORCE:
+            case K_NO:
+            case K_ENABLE:
+            case K_DISABLE:
+            case K_ALGORITHM:
+            case K_LOCK:
+            case K_CONVERT:
+            case K_PARTITION:
+            case K_ORDER:
+                return false;
+            default:
+                return true;        }
+    }
+
     /**
      * True when the pending {@code ON} opens the ON CONFLICT clause of the enclosing
      * INSERT rather than another trailing join condition: after a join, the trailing
@@ -20568,6 +20600,24 @@ AlterExpression AlterExpressionAddAlterModify():
                 |
                 LOOKAHEAD(2) alterExpressionColumnDataType = AlterExpressionColumnDataType()
                     { alterExp.addColDataType(alterExpressionColumnDataType); }
+                // T-SQL and Snowflake let one ADD list several columns and table
+                // constraints without repeating ADD.
+                (
+                    LOOKAHEAD(",", { alterExp.getOperation() == AlterOperation.ADD
+                            && (Dialect.SQLSERVER.name().equals(getAsString(Feature.dialect))
+                                || Dialect.SNOWFLAKE.name().equals(getAsString(Feature.dialect)))
+                            && isAlterAddListItemAhead() })
+                    "," { alterExp.setBareAddList(true); }
+                    (
+                        LOOKAHEAD({ getToken(1).kind == K_CONSTRAINT || getToken(1).kind == K_CHECK
+                                || getToken(1).kind == K_PRIMARY || getToken(1).kind == K_UNIQUE
+                                || getToken(1).kind == K_FOREIGN })
+                        element=TableConstraint(false) { setAlterTableElement(alterExp, element); }
+                        |
+                        alterExpressionColumnDataType = AlterExpressionColumnDataType()
+                            { alterExp.addColDataType(alterExpressionColumnDataType); }
+                    )
+                )*
             )
         )
         |

src/test/java/net/sf/jsqlparser/statement/alter/AlterTest.java

@@ -97,6 +97,49 @@ public void testAlterTableAddColumn_ColumnKeyWordImplicit() throws JSQLParserExc
         assertEquals("varchar (255)", colDataTypes.get(0).getColDataType().toString());
     }
 
+    @Test
+    public void testAlterTableAddColumnListTSql() throws JSQLParserException {
+        // T-SQL and Snowflake let one ADD list several columns without repeating ADD
+        Alter alter = (Alter) CCJSqlParserUtil.parse(
+                "ALTER TABLE t ADD a int, b varchar(10) NOT NULL, c int",
+                parser -> parser.withDialect(Dialect.SQLSERVER));
+        assertEquals(1, alter.getAlterExpressions().size());
+        AlterExpression alterExp = alter.getAlterExpressions().get(0);
+        assertEquals(AlterOperation.ADD, alterExp.getOperation());
+        List<ColumnDataType> colDataTypes = alterExp.getColDataTypeList();
+        assertEquals(3, colDataTypes.size());
+        assertEquals("a", colDataTypes.get(0).getColumnName());
+        assertEquals("b", colDataTypes.get(1).getColumnName());
+        assertEquals("varchar (10)", colDataTypes.get(1).getColDataType().toString());
+        assertEquals("c", colDataTypes.get(2).getColumnName());
+        assertDeparse(alter, "ALTER TABLE t ADD a int, b varchar (10) NOT NULL, c int");
+    }
+
+    @Test
+    public void testAlterTableAddColumnListWithConstraintTSql() throws JSQLParserException {
+        // T-SQL mixes column definitions and table constraints in one ADD list
+        Alter alter = (Alter) CCJSqlParserUtil.parse(
+                "ALTER TABLE t ADD a int, CONSTRAINT ck CHECK (a > 0)",
+                parser -> parser.withDialect(Dialect.SQLSERVER));
+        assertEquals(1, alter.getAlterExpressions().size());
+        AlterExpression alterExp = alter.getAlterExpressions().get(0);
+        assertEquals(AlterOperation.ADD, alterExp.getOperation());
+        assertEquals(1, alterExp.getColDataTypeList().size());
+        assertNotNull(alterExp.getConstraint());
+    }
+
+    @Test
+    public void testAlterTableAddColumnListSnowflake() throws JSQLParserException {
+        Alter alter = (Alter) CCJSqlParserUtil.parse(
+                "ALTER TABLE t ADD COLUMN a int, b int",
+                parser -> parser.withDialect(Dialect.SNOWFLAKE));
+        assertEquals(1, alter.getAlterExpressions().size());
+        List<ColumnDataType> colDataTypes =
+                alter.getAlterExpressions().get(0).getColDataTypeList();
+        assertEquals(2, colDataTypes.size());
+        assertDeparse(alter, "ALTER TABLE t ADD COLUMN a int, b int");
+    }
+
     @Test
     public void testAlterTableBackBrackets() throws JSQLParserException {
         String sql = "ALTER TABLE tablename add column (field  string comment 'aaaaa')";