ズボラエンジニアのChatGPT活用事例と今後やりたいこと！

import com.opencsv.bean.CsvBindByName;

public class UserCsvRecord {

    @CsvBindByName(column = "ID")
    private int id;

    @CsvBindByName(column = "氏名（漢字）")
    private String nameKanji;

    @CsvBindByName(column = "氏名（カナ）")
    private String nameKana;

    @CsvBindByName(column = "メールアドレス")
    private String email;
    
    ...
}

#!/bin/bash

# ファイル名指定（例: UserCsvRecord.java）
FILE="UserCsvRecord.java"

grep '@CsvBindByName(column *= *"' "$FILE" | \
  sed -E 's/.*@CsvBindByName\(column *= *"(.*?)"\).*/\1/' | \
  paste -sd, -

@Repository
class TodoRepository(
	private val dsl: DSLContext
) {
	// 今月最も時間がかかったタスクをサブクエリを使って取得する
	// サブクエリを使って、今月最も時間がかかったタスクを取得する
	fun fetchMostTimeConsumingTaskForThisMonth(): List<MaxDurationTodoDto> {
		val now = LocalDate.now()
		val currentMonthStart = now.withDayOfMonth(1).atStartOfDay()
		val currentMonthEnd = now.with(TemporalAdjusters.lastDayOfMonth()).atTime(23, 59)

		val durationField = timestampDiff(
			DatePart.MINUTE,
			TODO_LOGS.START_TIME.cast(Timestamp::class.java),
			TODO_LOGS.END_TIME.cast(Timestamp::class.java)
		)

		val rankField = rowNumber().over()
			.partitionBy(TODOS.USER_ID)
			.orderBy(durationField.desc())

		val doneTaskByUser = dsl
			.select(
				TODOS.USER_ID,
				TODOS.ID.`as`("todo_id"),
				TODOS.TITLE,
				durationField.`as`("duration_in_minutes"),
				rankField.`as`("rank")
			)
			.from(TODOS)
			.join(TODO_LOGS).on(TODOS.ID.eq(TODO_LOGS.TODO_ID))
			.where(
				TODOS.DONE.isTrue
					.and(TODO_LOGS.START_TIME.between(currentMonthStart, currentMonthEnd))
			).asTable("doneTaskByUser")

        // 重複を排除し、1位のタスクのみを取得
		val result = dsl
			.select(
				USERS.ID.`as`("user_id"),
				USERS.NAME.`as`("user_name"),
				doneTaskByUser.field("todo_id"),
				doneTaskByUser.field("title"),
				doneTaskByUser.field("duration_in_minutes")
			)
			.from(doneTaskByUser)
			.join(USERS).on(doneTaskByUser.field("user_id", Int::class.java)?.eq(USERS.ID))
			.where(doneTaskByUser.field("rank", Int::class.java)?.eq(1))
			.fetch()
		// 結果をMaxDurationTodoDtoにマッピング
		return result.map {
			MaxDurationTodoDto(
				userId = it.get("user_id", Int::class.java),
				userName = it.get("user_name", String::class.java),
				todoId = it.get("todo_id", Int::class.java),
				title = it.get("title", String::class.java),
				duration = it.get("duration_in_minutes", Int::class.java)
			)
		}
	}

-- 雑に考えてもらったテーブル設計（MySQL）
CREATE TABLE users (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(100) NOT NULL
);

CREATE TABLE todos (
  id INT PRIMARY KEY AUTO_INCREMENT,
  user_id INT NOT NULL,
  title VARCHAR(255) NOT NULL,
  done BOOLEAN NOT NULL DEFAULT FALSE,
  created_at DATETIME NOT NULL,
  FOREIGN KEY (user_id) REFERENCES users(id)
);

CREATE TABLE todo_logs (
  id INT PRIMARY KEY AUTO_INCREMENT,
  todo_id INT NOT NULL,
  start_time DATETIME NOT NULL,
  end_time DATETIME NOT NULL,
  FOREIGN KEY (todo_id) REFERENCES todos(id)
);