Databricks

rt-slowth · ‎10-09-2023

The Delta Table created as a result of the Dataframe returned by @dlt.create_table is confirmed to be overwritten when checked with the DECREASE HISTORY command.
I want this to be handled as a CRAS, or CREATE AS SELECT, but how can I do this in python code?

Kaniz · ‎10-10-2023

Hi @rt-slowth, Here is an example of how you can do this:

python
from pyspark.sql import SparkSession

spark = SparkSession.builder.getOrCreate()

# Assume df is your DataFrame
df = spark.sql("SELECT * FROM your_table")

# Write DataFrame to a new Delta table
df.write.format("delta").save("/path/to/new/delta/table")

In this example, replace "SELECT * FROM your_table" your SELECT query "/path/to/new/delta/table" with the exact path where you want to create the new Delta table. Please note that the DataFrame API's write method will overwrite the existing data at the specified path. If you want to append the data instead of overwriting, you can use the mode a method like this: df.write.format("delta").mode("append").save("/path/to/new/delta/table").

View solution in original post

Kaniz · ‎10-10-2023

Hi @rt-slowth , In Python, you can use the DeltaTableBuilder and DeltaColumnBuilder APIs to create new Delta tables programmatically, similar to a SQL CREATE TABLE AS SELECT (CTAS) statement.

rt-slowth · ‎10-10-2023

@Kaniz

If you don't mind me asking, can I see the code or documentation for this? I searched for DelataTableBuilder and only found Scala related stuff.

Kaniz · ‎10-10-2023

Hi @rt-slowth, Here is an example of how you can do this:

python
from pyspark.sql import SparkSession

spark = SparkSession.builder.getOrCreate()

# Assume df is your DataFrame
df = spark.sql("SELECT * FROM your_table")

# Write DataFrame to a new Delta table
df.write.format("delta").save("/path/to/new/delta/table")

In this example, replace "SELECT * FROM your_table" your SELECT query "/path/to/new/delta/table" with the exact path where you want to create the new Delta table. Please note that the DataFrame API's write method will overwrite the existing data at the specified path. If you want to append the data instead of overwriting, you can use the mode a method like this: df.write.format("delta").mode("append").save("/path/to/new/delta/table").

Kaniz · ‎11-14-2023

Hi @rt-slowth, To help us provide you with the most accurate information, could you please take a moment to review the responses and select the one that best answers your question?

This will also help other community members who may have similar questions. Thank you for your participation, and let us know if you need further assistance!