使用 python 將 SQL 輸出數據更新到相應工作表中的現有 Excel

Question

我是 Python 編程的新手，正在尋求一些幫助/指導來糾正我的 Python 代碼。

這是我的查詢。

1. 我有一個 Excel 文件，其中包含（7 個選項卡）。
2. 我有一個包含 7 個不同文本文件的文件夾，每個文本文件包含各自的 Tab SQL 查詢，每個文本文件名與 Excel 文件中可用的 Tab 名稱相同。

我編寫了一個 Python 代碼來一個接一個地遍歷所有文本文件，並執行每個文本文件 SQL 查詢以及輸出中將出現的任何數據，輸出數據應轉儲到相應工作表/選項卡中的現有 excel 文件中。 我正在使用 Pandas 來執行此操作，但是，代碼工作正常，但是在將數據更新到 excel 時，pandas 正在從文件中刪除所有現有工作表，並僅將當前輸出數據更新到 excel 文件中。

示例：如果 Python 代碼執行一個文本文件（文件名：數據）並且在執行此 SQL 查詢后我們得到了一些數據，這些數據應該轉儲到 excel 文件中（表名：數據）。

<pre><code>
import pypyodbc
import pandas as pd
import os
import ctypes
from pandas import ExcelWriter
fpath = r"C:\MNaveed\DataScience\Python Practice New\SQL Queries"
xlfile = r"C:\MNaveed\DataScience\Python Practice New\SQL Queries\Open_Case_Data.xlsx"
cnxn = pypyodbc.connect('Driver={SQL Server};Server=MyServerName;Database=MyDatabaseName;Trusted_Connection=Yes')
cursor = cnxn.cursor()

for subdir, dirs, files in os.walk(fpath):
    for file in files:
        #print(os.path.join(subdir,file))
        filepath = os.path.join(subdir,file)
        #print("FilePath: ", filepath)

        if filepath.endswith(".txt"):
            if file != "ClosedAging_Cont.txt":
                txtdata = open(filepath, 'r')
                script = txtdata.read().strip()
                txtdata.close()
                cursor.execute(script)
                if file == "ClosedAging.txt":
                    txtdata = open(os.path.join(subdir,"ClosedAging_Cont.txt"), 'r')
                    script = txtdata.read().strip()
                    txtdata.close()
                    cursor.execute(script)

                col = [desc[0] for desc in cursor.description]
                data = cursor.fetchall()
                df = pd.DataFrame(list(data),columns=col)

                #save_xls(df,xlfile)

                writer = pd.ExcelWriter(xlfile)
                flnm = file.replace('.txt','').strip()
                df.to_excel(writer,sheet_name=flnm,index=False)
                writer.save()

                print(file, " : Successfully Updated.")
            else:
                print(file, " : Ignoring this File")
        else:
            print(file, " : Ignoring this File")

ctypes.windll.user32.MessageBoxW(0,"Open Case Reporting Data Successfully Updated","Open Case Reporting",1)
</pre></code>

Answer 1

通過循環遍歷文本文件，您每次都會覆蓋循環內的 Excel 文件。 而是實例化 pd.ExcelWriter(xlfile) 並在循環外調用 writer.save() 。

以下示例改編自xlswriter 文檔

您可以在此處找到有關多張紙的更多信息： xlswriter 文檔 - 多張紙

import pandas as pd

# Create a Pandas Excel writer using XlsxWriter as the engine outside the loop.
writer = pd.ExcelWriter('pandas_simple.xlsx', engine='xlsxwriter')
# Sample loop, replace with directory browsing loop
for i in range(7):
    # Sample Pandas dataframe. Replace with SQL query and resulting data frame.
    df = pd.DataFrame({'DataFromSQLQuery': ['SQL query result {0}'.format(i)]})
    # Convert the dataframe to an XlsxWriter Excel object.
    df.to_excel(writer, sheet_name='Sheet{0}'.format(i))
# Close the Pandas Excel writer and output the Excel file.
writer.save()

以下代碼解決了具體問題，但未經測試。

import pypyodbc
import pandas as pd
import os
import ctypes
from pandas import ExcelWriter

fpath = r"C:\MNaveed\DataScience\Python Practice New\SQL Queries"
xlfile = r"C:\MNaveed\DataScience\Python Practice New\SQL Queries\Open_Case_Data.xlsx"
cnxn = pypyodbc.connect('Driver={SQL Server};Server=MyServerName;Database=MyDatabaseName;Trusted_Connection=Yes')
cursor = cnxn.cursor()

# Create a Pandas Excel writer using XlsxWriter as the engine outside the loop
writer = pd.ExcelWriter('pandas_simple.xlsx', engine='xlsxwriter')

# File loop
for subdir, dirs, files in os.walk(fpath):
    for file in files:
        filepath = os.path.join(subdir,file)
        if filepath.endswith(".txt"):
            if file != "ClosedAging_Cont.txt":
                txtdata = open(filepath, 'r')
                script = txtdata.read().strip()
                txtdata.close()
                cursor.execute(script)
                if file == "ClosedAging.txt":
                    txtdata = open(os.path.join(subdir,"ClosedAging_Cont.txt"), 'r')
                    script = txtdata.read().strip()
                    txtdata.close()
                    cursor.execute(script)

                col = [desc[0] for desc in cursor.description]
                data = cursor.fetchall()

                # Data frame from original question
                df = pd.DataFrame(list(data),columns=col)

                # Convert the dataframe to an XlsxWriter Excel object
                flnm = file.replace('.txt','').strip()
                df.to_excel(writer, sheet_name=flnm, index=False)

                print(file, " : Successfully Updated.")
            else:
                print(file, " : Ignoring this File")
        else:
            print(file, " : Ignoring this File")

# Close the Pandas Excel writer and output the Excel file
writer.save()

ctypes.windll.user32.MessageBoxW(0,"Open Case Reporting Data Successfully Updated","Open Case Reporting",1)