polars duckdb

 import polars as pl

import polars.selectors as cs

import duckdb

con = duckdb.connect("/mnt/c/Users/Administrator/Downloads/流感肺炎/fy.db")

# 获取所有表名

tables = con.execute("SHOW TABLES").pl()

print(tables)

# 查看 test 表的列信息

schema = con.execute("DESCRIBE test").pl()

print(schema)

# 读数据库表

test = con.execute("""

    SELECT * FROM test

""").pl(lazy=True)

# 比较慢

# test2 = pl.read_database("SELECT * FROM test", connection=con).lazy()

test.collect_schema()

# 关闭连接

con.close()

#######################

import polars as pl

import polars.selectors as cs

import duckdb

con = duckdb.connect("/mnt/c/Users/Administrator/Downloads/流感肺炎/fy.db")

temp = (

    pl.scan_csv(

        "/mnt/c/Users/Administrator/Downloads/流感肺炎/接种.csv", infer_schema=None

    )

    .rename(lambda col: col.lower())

    .with_columns(

        pl.col("csrq").str.to_date(strict=False),

        pl.col("jz_sj").str.to_datetime(strict=False).dt.date(),

    )

    .with_columns(age=((pl.col("jz_sj") - pl.col("csrq")).dt.total_days()) / 365)

    .rename({'???"grda_code"': "grda_code"})

    .collect(engine="streaming")

)

# 写入数据库

con.execute("CREATE OR REPLACE TABLE test AS SELECT * FROM temp")

# 创建一个表作为测试

con.execute("""

    CREATE TABLE lg AS

    SELECT * FROM read_csv_auto(

        './接种.csv',

        types={'CSRQ': 'VARCHAR','JZ_SJ':'VARCHAR'},

        dateformat='%Y/%m/%d',

        timestampformat='%Y/%m/%d %H:%M:%S'

    )

""")

##较慢 mamba install SQLAlchemy duckdb-engine

import polars as pl

from sqlalchemy import create_engine

conn = create_engine(f"duckdb:///fy.db")

query = "SELECT * FROM test"

test = pl.read_database(query=query, connection=conn.connect())