select rank() over(partition By key_column order By row_priority in (select row_priority from cte ))帮我改一下
时间: 2024-02-14 21:15:21 浏览: 69
根据您提供的 SQL 语句,您可能想要在 `select` 语句中使用 `rank()` 窗口函数,并将其与子查询和公共表表达式(CTE)结合使用。但是,您的 SQL 语法存在语法错误。我来帮您修正一下:
```
WITH cte AS (
SELECT key_column, row_priority
FROM your_table
WHERE some_condition
)
SELECT key_column, row_priority, RANK() OVER (
PARTITION BY key_column
ORDER BY (SELECT row_priority FROM cte)
) AS ranking
FROM your_table
WHERE some_condition
```
上面的 SQL 语句中,首先使用 CTE `cte` 获取 `key_column` 和 `row_priority` 字段的值。然后,在主查询中,使用 `RANK()` 窗口函数对 `key_column` 进行分区,并按照子查询中的 `row_priority` 字段进行排序。最后,从 `your_table` 表中选择分区和排序后的结果,并添加名为 `ranking` 的新列。
请注意,我在假设您使用的是 PostgreSQL 数据库,因此可以使用窗口函数。如果您使用的是其他数据库,可能需要使用不同的语法或函数来实现相似的功能。
相关问题
with cte as{ select case when co1,co2,co3 有值 then co1,co2,co3 else null end as new_column, 0 as row_priority from new_df union all select case when co1,co2,co3 有值 then co1,co2,co3 else null end as order_column, 1 as row_priority from order_df } selct col,co2 from (select col,co2, rank() over(partition By key_column order By (select row_priority from cte )) as rank where rank=1) main这样写有没有漏写下面的语句和new_df_cols = new_df.columns old_df_cols = older_df.columns total = set(new_df_cols + old_df_cols) new_df = new_df.select(*self.fill_empty_colums(new_df_cols, total)).withColumn("row_priority",F.lit(0)) older_df = older_df.select(*self.fill_empty_colums(old_df_cols, total)).withColumn("row_priority",F.lit(1)) key_column = [F.col(column_name) for column_name in key_columns] merge_spec = Window.partitionBy(key_column).orderBy("row_priority") ranked_df=new_df.unionByName(older_df).withColumn("rank", F.rank().over(merge_spec)) return self.update_audit_created_column(ranked_df,key_column).where(F.col("rank") == 1).drop("rank", "row_priority")
这段代码的功能是将两个DataFrame对象(new_df和older_df)按照指定的key_column进行合并,并为每个合并后的行添加一个rank列,然后选择每个key_column分组中排名为1的行,并删除rank和row_priority列。其中,fill_empty_colums函数是用来填充空列的,update_audit_created_column函数是用来更新审计创建列的。
new_df_cols = new_df.columns old_df_cols = older_df.columns total = set(new_df_cols + old_df_cols) new_df = new_df.select(*self.fill_empty_colums(new_df_cols, total)).withColumn("row_priority",F.lit(0)) older_df = older_df.select(*self.fill_empty_colums(old_df_cols, total)).withColumn("row_priority",F.lit(1)) key_column = [F.col(column_name) for column_name in key_columns] merge_spec = Window.partitionBy(key_column).orderBy("row_priority") ranked_df=new_df.unionByName(older_df).withColumn("rank", F.rank().over(merge_spec)) return self.update_audit_created_column(ranked_df,key_column).where(F.col("rank") == 1).drop("rank", "row_priority")
这段代码用 PySpark 实现了对两个 DataFrame 进行合并和去重的操作,并添加了一些元数据信息。下面是使用 SQL 实现的代码:
```sql
-- 选取需要合并的列名
WITH new_cols AS (
SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'new_df'
),
old_cols AS (
SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'older_df'
),
cols AS (
SELECT DISTINCT COLUMN_NAME
FROM (
SELECT COLUMN_NAME FROM new_cols
UNION ALL
SELECT COLUMN_NAME FROM old_cols
)
),
-- 对 new_df 填充空缺的列,并添加 "row_priority" 列
new_df_filled AS (
SELECT COALESCE(col1, '') AS col1, COALESCE(col2, '') AS col2, ..., COALESCE(colN, '') AS colN, 0 AS row_priority
FROM new_df
),
new_df_selected AS (
SELECT *, ROW_NUMBER() OVER (PARTITION BY key_column ORDER BY row_priority) AS rank
FROM (
-- 选取 new_df 中的列,包括填充空缺的列和 "row_priority" 列
SELECT col1, col2, ..., colN, row_priority
FROM new_df_filled
-- 生成 key_column 列,用于分组
CROSS JOIN (SELECT col1 AS key_column FROM new_df_filled) key_columns
)
),
-- 对 older_df 填充空缺的列,并添加 "row_priority" 列
old_df_filled AS (
SELECT COALESCE(col1, '') AS col1, COALESCE(col2, '') AS col2, ..., COALESCE(colN, '') AS colN, 1 AS row_priority
FROM older_df
),
old_df_selected AS (
SELECT *, ROW_NUMBER() OVER (PARTITION BY key_column ORDER BY row_priority) AS rank
FROM (
-- 选取 older_df 中的列,包括填充空缺的列和 "row_priority" 列
SELECT col1, col2, ..., colN, row_priority
FROM old_df_filled
-- 生成 key_column 列,用于分组
CROSS JOIN (SELECT col1 AS key_column FROM old_df_filled) key_columns
)
),
-- 合并两个 DataFrame,并去重
merged_df AS (
SELECT * FROM new_df_selected
UNION ALL
SELECT * FROM old_df_selected
),
-- 选取合并后的第一行
final_df AS (
SELECT *, ROW_NUMBER() OVER (PARTITION BY key_column ORDER BY rank) AS row_num
FROM merged_df
)
SELECT col1, col2, ..., colN
FROM final_df
WHERE row_num = 1
```
这段 SQL 代码的实现原理与 PySpark 代码相同,主要分为以下几个步骤:
1. 获取需要合并的列名。
2. 对 new_df 和 older_df 分别进行填充空缺列、添加 "row_priority" 列和选取列的操作,生成 new_df_selected 和 old_df_selected 两个数据集。
3. 将 two_df_selected 进行合并,并添加 rank 列,用于去重。
4. 选取合并后的第一行,得到最终的去重结果。
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