# UPDATE FROM
#### 功能描述
将源表中某个字段的值更新到目标表的字段。
#### 血缘解析支持的语法格式
```
UPDATE {schema_name}.{table_name1} SET col1 = b.col2 FROM {schema_name}.{table_name2} b
```
#### 语句示例
```
UPDATE public.dws_table_2 target
SET 
    target.col1 = source.col1,
    target.col2 = source.col2,
    target.update_time = source.update_time
FROM public.dws_table_1 source
WHERE target.id = source.id;
```