英文:
"If exists" in databricks
问题
在Databricks中，您可以使用SQL或PySpark来实现类似的功能。以下是在Databricks中使用SQL的示例：
-- 使用SQL在Databricks中检查日期并执行插入操作
INSERT INTO DWH.F_TIMESHEET_FREEZE
SELECT *
FROM (
SELECT CAST(SnapshotDate AS DATE) AS SnapshotDate
FROM CONFIG.SnapshotDateTables
) AS subquery
WHERE EXISTS (
SELECT 1
FROM subquery
WHERE DATEADD(day, 1, SnapshotDate) = CAST(GETDATE() AS DATE)
);
这段SQL代码首先将SnapshotDate列的日期数据转换为日期类型，并将其存储在子查询中。然后，它在子查询中检查日期条件，如果满足条件，则执行插入操作。
如果您更喜欢使用PySpark，以下是使用PySpark的等效示例：
from pyspark.sql import SparkSession
from pyspark.sql.functions import date_add, col
# 创建Spark会话
spark = SparkSession.builder.appName("DateCheckExample").getOrCreate()
# 从CONFIG.SnapshotDateTables中读取数据
snapshot_date_df = spark.sql("SELECT CAST(SnapshotDate AS DATE) AS SnapshotDate FROM CONFIG.SnapshotDateTables")
# 添加一天到日期并检查条件
result_df = snapshot_date_df.filter(date_add(col("SnapshotDate"), 1) == col("current_date"))
# 如果条件满足，执行插入操作
result_df.write.mode("append").insertInto("DWH.F_TIMESHEET_FREEZE")
# 停止Spark会话
spark.stop()
这段PySpark代码首先创建了一个Spark会话，然后从CONFIG.SnapshotDateTables中读取数据。接下来，它使用date_add函数添加一天到日期并检查条件。如果条件满足，它将数据插入到DWH.F_TIMESHEET_FREEZE表中。最后，它停止了Spark会话。
英文:
I have statement in t-sql. which checks the date and if its true then it will continue execution (insert into).
IF EXISTS (SELECT dateadd(day,+1,CAST(SnapshotDate as date)) FROM CONFIG.[SnapshotDateTables] WHERE dateadd(day,+1,CAST(SnapshotDate as date)) = CAST(GETDATE() as date))
INSERT INTO [DWH].[F_TIMESHEET_FREEZE]
How can I achiave similar thing in databricks using sql or pyspark, no preference.
答案1
得分: 1
你可以尝试在Databricks SQL中使用以下代码中建议的where子句：
%sql
insert into <table_name1> select [column1],[column2].. from <table_name2> where [column] = <Value>;
请查看以下演示：
这里我有sample2表中的2行数据。
我已经创建了必要的条件，我们需要根据条件插入值，我正在按以下方式插入表。
%sql
insert into sample1 select * from sample2 where name = 'Laddu';
当条件为真时：
当条件为假时：
英文:
You can try the below in databricks SQL using where clause as suggested in comments.
%sql
insert into <table_name1> select [column1],[column2].. from <table_name2> where [column] = <Value>;
Go through the below demonstration:
Here I have 2 rows in sample2 table.
I have created the required where we need to insert values and I am inserting the table on condition like below.
%sql
insert into sample1 select * from sample2 where name = 'Laddu';
when condition is true:
when condition is false:
答案2
得分: 1
如果您在Databricks中使用SQL：
IF EXISTS (
SELECT DATE_ADD(SnapshotDate, INTERVAL 1 DAY)
FROM CONFIG.SnapshotDateTables
WHERE DATE_ADD(SnapshotDate, INTERVAL 1 DAY) = CURRENT_DATE()
)
INSERT INTO DWH.F_TIMESHEET_FREEZE
SELECT ...
然后将SELECT ...替换为您要插入到DWH.F_TIMESHEET_FREEZE表中的查询。
如果您在Databricks中使用PySpark：
from pyspark.sql.functions import col, expr
snapshot_exists = spark.sql("""
SELECT DATE_ADD(SnapshotDate, INTERVAL 1 DAY) AS NextSnapshotDate
FROM CONFIG.SnapshotDateTables
WHERE DATE_ADD(SnapshotDate, INTERVAL 1 DAY) = CURRENT_DATE()
""").count() > 0
if snapshot_exists:
df_insert = ...
df_insert.write.insertInto("DWH.F_TIMESHEET_FREEZE")
将df_insert = ...替换为您用于插入到DWH.F_TIMESHEET_FREEZE表的DataFrame创建逻辑。
英文:
If you are using SQL in Databricks:
IF EXISTS (
SELECT DATE_ADD(SnapshotDate, INTERVAL 1 DAY)
FROM CONFIG.SnapshotDateTables
WHERE DATE_ADD(SnapshotDate, INTERVAL 1 DAY) = CURRENT_DATE()
)
INSERT INTO DWH.F_TIMESHEET_FREEZE
SELECT ...
Then replace SELECT ... with your query for inserting into the DWH.F_TIMESHEET_FREEZE table.
If you are using PySpark in Databricks:
from pyspark.sql.functions import col, expr
snapshot_exists = spark.sql("""
SELECT DATE_ADD(SnapshotDate, INTERVAL 1 DAY) AS NextSnapshotDate
FROM CONFIG.SnapshotDateTables
WHERE DATE_ADD(SnapshotDate, INTERVAL 1 DAY) = CURRENT_DATE()
""").count() > 0
if snapshot_exists:
df_insert = ...
df_insert.write.insertInto("DWH.F_TIMESHEET_FREEZE")
Replace df_insert = ... with your DataFrame creation logic for inserting into the DWH.F_TIMESHEET_FREEZE table.
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