检查 pyodbc 列中精确字符串的出现（频率）

Question

所以我需要创建一个简单的函数来检查列中特定字符串 'c' 的出现次数，然后除以总数。之前没有使用过 pyodbc，一直卡在一开始。

def get_c_i(c):
    cursor.execute('select count (*) from conditions')
    total = cursor.fetchone()[0]
    print(total)
    cursor.execute('select Name from Conditions where Name LIKE c')
    freq = cursor.fetchone()[0]
    print(freq)
    cursor.close()

Traceback (most recent call last):
  File "F:/Work/db/eyetoai/eyetoai/database/predict.py", line 34, in <module>
    get_c_i('Fibroadenoma')
  File "F:/Work/db/eyetoai/eyetoai/database/predict.py", line 27, in get_c_i
    cursor.execute('select Name from Conditions where Name LIKE c')
pyodbc.ProgrammingError: ('42S22', "[42S22] [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]Invalid column name 'c'. (207) (SQLExecDirectW)")

Answer 1

您似乎想要这样的东西：

cursor.execute("SELECT COUNT(*) FROM Conditions")
total = cursor.fetchval()
cursor.execute("SELECT COUNT(*) FROM Conditions WHERE Name=?", "c")
freq = cursor.fetchval()
print("{0} / {1} = {2}".format(freq, total, freq/total))  # check results

检查 pyodbc 列中精确字符串的出现（频率）

Check occurrence (frequency) of exact string in a column in pyodbc

python

sql

pyodbc