How to use

unparseCall

method

in

org.apache.calcite.sql.SqlDialect

 @Override public void unparseCall(SqlWriter writer, SqlCall call,
   int leftPrec, int rightPrec) {
  if (call instanceof SqlSelect) {
   callsUnparseCallOnSqlSelect[0] = true;
  }
  super.unparseCall(writer, call, leftPrec, rightPrec);
 }
};

 @Override public void unparseCall(SqlWriter writer, SqlCall call,
   int leftPrec, int rightPrec) {
  if (call instanceof SqlSelect) {
   callsUnparseCallOnSqlSelect[0] = true;
  }
  super.unparseCall(writer, call, leftPrec, rightPrec);
 }
};

@Override public void unparseCall(SqlWriter writer, SqlCall call,
  int leftPrec, int rightPrec) {
 switch (call.getKind()) {
 case FLOOR:
  if (call.operandCount() != 2) {
   super.unparseCall(writer, call, leftPrec, rightPrec);
   return;
  }
  unparseFloor(writer, call);
  break;
 default:
  super.unparseCall(writer, call, leftPrec, rightPrec);
 }
}

@Override public void unparseCall(SqlWriter writer, SqlCall call,
  int leftPrec, int rightPrec) {
 switch (call.getKind()) {
 case FLOOR:
  if (call.operandCount() != 2) {
   super.unparseCall(writer, call, leftPrec, rightPrec);
   return;
  }
  unparseFloor(writer, call);
  break;
 default:
  super.unparseCall(writer, call, leftPrec, rightPrec);
 }
}

@Override public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
 if (!writer.inQuery()) {
  // If this SELECT is the topmost item in a sub-query, introduce a new
  // frame. (The topmost item in the sub-query might be a UNION or
  // ORDER. In this case, we don't need a wrapper frame.)
  final SqlWriter.Frame frame =
    writer.startList(SqlWriter.FrameTypeEnum.SUB_QUERY, "(", ")");
  writer.getDialect().unparseCall(writer, this, 0, 0);
  writer.endList(frame);
 } else {
  writer.getDialect().unparseCall(writer, this, leftPrec, rightPrec);
 }
}

@Override public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
 if (!writer.inQuery()) {
  // If this SELECT is the topmost item in a sub-query, introduce a new
  // frame. (The topmost item in the sub-query might be a UNION or
  // ORDER. In this case, we don't need a wrapper frame.)
  final SqlWriter.Frame frame =
    writer.startList(SqlWriter.FrameTypeEnum.SUB_QUERY, "(", ")");
  writer.getDialect().unparseCall(writer, this, 0, 0);
  writer.endList(frame);
 } else {
  writer.getDialect().unparseCall(writer, this, leftPrec, rightPrec);
 }
}

@Override public void unparseCall(SqlWriter writer, SqlCall call,
  int leftPrec, int rightPrec) {
 if (call.getOperator() == SqlStdOperatorTable.SUBSTRING) {
  if (call.operandCount() != 3) {
   throw new IllegalArgumentException("MSSQL SUBSTRING requires FROM and FOR arguments");
  }
  SqlUtil.unparseFunctionSyntax(MSSQL_SUBSTRING, writer, call);
 } else {
  switch (call.getKind()) {
  case FLOOR:
   if (call.operandCount() != 2) {
    super.unparseCall(writer, call, leftPrec, rightPrec);
    return;
   }
   unparseFloor(writer, call);
   break;
  default:
   super.unparseCall(writer, call, leftPrec, rightPrec);
  }
 }
}

@Override public void unparseCall(SqlWriter writer, SqlCall call,
  int leftPrec, int rightPrec) {
 if (call.getOperator() == SqlStdOperatorTable.SUBSTRING) {
  if (call.operandCount() != 3) {
   throw new IllegalArgumentException("MSSQL SUBSTRING requires FROM and FOR arguments");
  }
  SqlUtil.unparseFunctionSyntax(MSSQL_SUBSTRING, writer, call);
 } else {
  switch (call.getKind()) {
  case FLOOR:
   if (call.operandCount() != 2) {
    super.unparseCall(writer, call, leftPrec, rightPrec);
    return;
   }
   unparseFloor(writer, call);
   break;
  default:
   super.unparseCall(writer, call, leftPrec, rightPrec);
  }
 }
}

public void unparse(
  SqlWriter writer,
  int leftPrec,
  int rightPrec) {
 final SqlOperator operator = getOperator();
 final SqlDialect dialect = writer.getDialect();
 if (leftPrec > operator.getLeftPrec()
   || (operator.getRightPrec() <= rightPrec && (rightPrec != 0))
   || writer.isAlwaysUseParentheses() && isA(SqlKind.EXPRESSION)) {
  final SqlWriter.Frame frame = writer.startList("(", ")");
  dialect.unparseCall(writer, this, 0, 0);
  writer.endList(frame);
 } else {
  dialect.unparseCall(writer, this, leftPrec, rightPrec);
 }
}

public void unparse(
  SqlWriter writer,
  int leftPrec,
  int rightPrec) {
 final SqlOperator operator = getOperator();
 final SqlDialect dialect = writer.getDialect();
 if (leftPrec > operator.getLeftPrec()
   || (operator.getRightPrec() <= rightPrec && (rightPrec != 0))
   || writer.isAlwaysUseParentheses() && isA(SqlKind.EXPRESSION)) {
  final SqlWriter.Frame frame = writer.startList("(", ")");
  dialect.unparseCall(writer, this, 0, 0);
  writer.endList(frame);
 } else {
  dialect.unparseCall(writer, this, leftPrec, rightPrec);
 }
}

 @Override public void unparseCall(SqlWriter writer, SqlCall call,
   int leftPrec, int rightPrec) {
  switch (call.getKind()) {
  case FLOOR:
   if (call.operandCount() != 2) {
    super.unparseCall(writer, call, leftPrec, rightPrec);
    return;
   }

   final SqlLiteral timeUnitNode = call.operand(1);
   final TimeUnitRange timeUnit = timeUnitNode.getValueAs(TimeUnitRange.class);

   SqlCall call2 = SqlFloorFunction.replaceTimeUnitOperand(call, timeUnit.name(),
     timeUnitNode.getParserPosition());
   SqlFloorFunction.unparseDatetimeFunction(writer, call2, "DATE_TRUNC", false);
   break;

  default:
   super.unparseCall(writer, call, leftPrec, rightPrec);
  }
 }
}

@Override public void unparseCall(SqlWriter writer, SqlCall call,
  int leftPrec, int rightPrec) {
 switch (call.getKind()) {
 case FLOOR:
  if (call.operandCount() != 2) {
   super.unparseCall(writer, call, leftPrec, rightPrec);
   return;
  }
  final SqlLiteral timeUnitNode = call.operand(1);
  final TimeUnitRange timeUnit = timeUnitNode.getValueAs(TimeUnitRange.class);
  final String translatedLit = convertTimeUnit(timeUnit);
  SqlCall call2 = SqlFloorFunction.replaceTimeUnitOperand(call, translatedLit,
    timeUnitNode.getParserPosition());
  SqlFloorFunction.unparseDatetimeFunction(writer, call2, "TRUNC", true);
  break;
 default:
  super.unparseCall(writer, call, leftPrec, rightPrec);
 }
}

 @Override public void unparseCall(SqlWriter writer, SqlCall call,
   int leftPrec, int rightPrec) {
  switch (call.getKind()) {
  case FLOOR:
   if (call.operandCount() != 2) {
    super.unparseCall(writer, call, leftPrec, rightPrec);
    return;
   }

   final SqlLiteral timeUnitNode = call.operand(1);
   final TimeUnitRange timeUnit = timeUnitNode.getValueAs(TimeUnitRange.class);

   SqlCall call2 = SqlFloorFunction.replaceTimeUnitOperand(call, timeUnit.name(),
     timeUnitNode.getParserPosition());
   SqlFloorFunction.unparseDatetimeFunction(writer, call2, "DATE_TRUNC", false);
   break;

  default:
   super.unparseCall(writer, call, leftPrec, rightPrec);
  }
 }
}

@Override public void unparseCall(SqlWriter writer, SqlCall call,
  int leftPrec, int rightPrec) {
 switch (call.getKind()) {
 case FLOOR:
  if (call.operandCount() != 2) {
   super.unparseCall(writer, call, leftPrec, rightPrec);
   return;
  }
  final SqlLiteral timeUnitNode = call.operand(1);
  final TimeUnitRange timeUnit = timeUnitNode.getValueAs(TimeUnitRange.class);
  final String translatedLit = convertTimeUnit(timeUnit);
  SqlCall call2 = SqlFloorFunction.replaceTimeUnitOperand(call, translatedLit,
    timeUnitNode.getParserPosition());
  SqlFloorFunction.unparseDatetimeFunction(writer, call2, "TRUNC", true);
  break;
 default:
  super.unparseCall(writer, call, leftPrec, rightPrec);
 }
}

 @Override public void unparseCall(SqlWriter writer, SqlCall call,
   int leftPrec, int rightPrec) {
  if (call.getOperator() == SqlStdOperatorTable.SUBSTRING) {
   SqlUtil.unparseFunctionSyntax(OracleSqlOperatorTable.SUBSTR, writer, call);
  } else {
   switch (call.getKind()) {
   case FLOOR:
    if (call.operandCount() != 2) {
     super.unparseCall(writer, call, leftPrec, rightPrec);
     return;
    }

    final SqlLiteral timeUnitNode = call.operand(1);
    final TimeUnitRange timeUnit = timeUnitNode.getValueAs(TimeUnitRange.class);

    SqlCall call2 = SqlFloorFunction.replaceTimeUnitOperand(call, timeUnit.name(),
      timeUnitNode.getParserPosition());
    SqlFloorFunction.unparseDatetimeFunction(writer, call2, "TRUNC", true);
    break;

   default:
    super.unparseCall(writer, call, leftPrec, rightPrec);
   }
  }
 }
}

 @Override public void unparseCall(SqlWriter writer, SqlCall call,
   int leftPrec, int rightPrec) {
  if (call.getOperator() == SqlStdOperatorTable.SUBSTRING) {
   SqlUtil.unparseFunctionSyntax(OracleSqlOperatorTable.SUBSTR, writer, call);
  } else {
   switch (call.getKind()) {
   case FLOOR:
    if (call.operandCount() != 2) {
     super.unparseCall(writer, call, leftPrec, rightPrec);
     return;
    }

    final SqlLiteral timeUnitNode = call.operand(1);
    final TimeUnitRange timeUnit = timeUnitNode.getValueAs(TimeUnitRange.class);

    SqlCall call2 = SqlFloorFunction.replaceTimeUnitOperand(call, timeUnit.name(),
      timeUnitNode.getParserPosition());
    SqlFloorFunction.unparseDatetimeFunction(writer, call2, "TRUNC", true);
    break;

   default:
    super.unparseCall(writer, call, leftPrec, rightPrec);
   }
  }
 }
}