python - 从使用绑定(bind)变量的数据库查询创建 Pandas 数据框

Question

我正在使用 Oracle 数据库。我能做到这么多:

    import pandas as pd
    import pandas.io.sql as psql
    import cx_Oracle as odb
    conn = odb.connect(_user +'/'+ _pass +'@'+ _dbenv)

    sqlStr = "SELECT * FROM customers"
    df = psql.frame_query(sqlStr, conn)

但是我不知道如何处理绑定(bind)变量，像这样:

    sqlStr = """SELECT * FROM customers 
                WHERE id BETWEEN :v1 AND :v2
             """

我试过这些变体:

   params  = (1234, 5678)
   params2 = {"v1":1234, "v2":5678}

   df = psql.frame_query((sqlStr,params), conn)
   df = psql.frame_query((sqlStr,params2), conn)
   df = psql.frame_query(sqlStr,params, conn)
   df = psql.frame_query(sqlStr,params2, conn)

以下作品:

   curs = conn.cursor()
   curs.execute(sqlStr, params)
   df = pd.DataFrame(curs.fetchall())
   df.columns = [rec[0] for rec in curs.description]

但这个解决方案只是...不够优雅。如果可以，我想在不创建游标对象的情况下执行此操作。有没有办法只使用 pandas 来完成整个事情？

Answer 1

尝试使用 pandas.io.sql.read_sql_query。我用的是pandas 0.20.1版本，我用过，成功了:

import pandas as pd
import pandas.io.sql as psql
import cx_Oracle as odb
conn = odb.connect(_user +'/'+ _pass +'@'+ _dbenv)

sqlStr = """SELECT * FROM customers 
            WHERE id BETWEEN :v1 AND :v2
"""
pars = {"v1":1234, "v2":5678}
df = psql.frame_query(sqlStr, conn, params=pars)