CREATE
In Polars, the SQLContext
provides a way to execute SQL statements against LazyFrames
and DataFrames
using SQL syntax. One of the SQL statements that can be executed using SQLContext
is the CREATE TABLE
statement, which is used to create a new table.
The syntax for the CREATE TABLE
statement in Polars is as follows:
CREATE TABLE table_name
AS
SELECT ...
In this syntax, table_name
is the name of the new table that will be created, and SELECT ...
is a SELECT statement that defines the data that will be inserted into the table.
Here's an example of how to use the CREATE TABLE
statement in Polars:
data = {"name": ["Alice", "Bob", "Charlie", "David"], "age": [25, 30, 35, 40]}
df = pl.LazyFrame(data)
ctx = pl.SQLContext(my_table=df, eager=True)
result = ctx.execute(
"""
CREATE TABLE older_people
AS
SELECT * FROM my_table WHERE age > 30
"""
)
print(ctx.execute("SELECT * FROM older_people"))
shape: (2, 2)
┌─────────┬─────┐
│ name ┆ age │
│ --- ┆ --- │
│ str ┆ i64 │
╞═════════╪═════╡
│ Charlie ┆ 35 │
│ David ┆ 40 │
└─────────┴─────┘
In this example, we use the execute()
method of the SQLContext
to execute a CREATE TABLE
statement that creates a new table called older_people
based on a SELECT statement that selects all rows from the my_table
DataFrame where the age
column is greater than 30.
Note
Note that the result of a CREATE TABLE
statement is not the table itself. The table is registered in the SQLContext
. In case you want to turn the table back to a DataFrame
you can use a SELECT * FROM ...
statement