# create table
Using create table command to create a bigquery table , give me a example 
1 no null
2 string 
3 boolean
4 timestamp

Sure! Here’s a full example of a CREATE TABLE command in BigQuery that matches your requirement:

⸻

✅ Example:
```sql
CREATE TABLE my_dataset.my_table (
    id STRING NOT NULL,          -- string and not null
    is_active BOOLEAN NOT NULL,  -- boolean and not null
    created_at TIMESTAMP NOT NULL  -- timestamp and not null
);
```


⸻

✅ Explanation:

| Column Name | Data Type | Constraint |
|------------|-----------|------------|
| id         | STRING    | NOT NULL   |
| is_active  | BOOLEAN   | NOT NULL   |
| created_at | TIMESTAMP | NOT NULL   |



⸻

Notes:
	•	In BigQuery, NOT NULL is equivalent to setting the column mode to REQUIRED.
	•	CREATE TABLE will automatically mark these fields as REQUIRED instead of NULLABLE when using NOT NULL.

⸻

If you want, I can also show you:
	1.	How to make the same table using JSON Schema (for API or bq CLI usage)
	2.	How to insert into this table correctly

Reply with yes if you want me to continue.

# BigQuery 表结构定义

## 数据表设计

### 字段说明

```sql
CREATE TABLE IF NOT EXISTS `project_id.dataset_id.table_name` (
  id STRING,           -- 记录唯一标识
  data STRING,         -- 记录数据(JSON格式)
  CreateTime TIMESTAMP, -- 记录创建时间(仅首次创建时设置)
  UpdateTime TIMESTAMP  -- 记录更新时间(每次更新都会更新)
);
```

### 字段用途

- CreateTime: 仅在记录首次创建时设置，后续更新不会改变此值
- UpdateTime: 每次记录发生更新时都会更新此字段值

### 数据同步逻辑

1. 首次创建记录:
   ```sql
   INSERT INTO `table_name` (id, data, CreateTime, UpdateTime)
   VALUES ('record_id', 'data_json', CURRENT_TIMESTAMP(), CURRENT_TIMESTAMP());
   ```

2. 更新已有记录:
   ```sql
   UPDATE `table_name`
   SET data = 'new_data_json',
       UpdateTime = CURRENT_TIMESTAMP()
   WHERE id = 'record_id'
   AND data != 'new_data_json';
   ```

### 增量同步策略

1. 获取需要同步的数据:
   ```sql
   SELECT id, data, UpdateTime
   FROM `table_name`
   WHERE UpdateTime >= 'last_sync_time';
   ```

2. 比较数据变化:
   - 如果记录不存在，执行INSERT操作并设置CreateTime和UpdateTime
   - 如果记录存在且数据有变化，执行UPDATE操作只更新UpdateTime
   - 如果记录存在但数据无变化，不执行任何操作