Python的SQL ValueError異常

Question

我收到以下錯誤：

query=query%db.literal(args) 
ValueError: Unsupported Format character 'P' (0x50) 

這裏是我的查詢中，從蟒蛇執行（注意phraseList是一個列表）

for elem in phraseList: 
    cursor.execute("""SELECT PHRASE,COUNT(CASEID) FROM TEST.NER WHERE LABEL LIKE '%PART%' \ 
    AND CASEID IN (SELECT DISTINCT CASEID FROM TEST.NER WHERE LABEL LIKE '%CONDITION%'\ 
    AND PHRASE LIKEPHRASE LIKE %s""",(elem,)) 

Answer 1

MySQLdb重載Python字符串格式化語法和%P部分%PART%被視爲字符串格式化表達式。

爲了防止這種情況，你需要的字符一倍至%%：

for elem in phraseList: 
    cursor.execute("""SELECT PHRASE,COUNT(CASEID) FROM TEST.NER WHERE LABEL LIKE '%%PART%%' \ 
    AND CASEID IN (SELECT DISTINCT CASEID FROM TEST.NER WHERE LABEL LIKE '%%CONDITION%%'\ 
    AND PHRASE LIKEPHRASE LIKE %s""",(elem,)) 

Answer 2

這裏是什麼讓錯誤消失：

for elem in phraseList: 
    part='%part%' 
    condition='%condition%' 
    query="SELECT PHRASE,COUNT(CASEID) FROM TEST.NER WHERE LABEL LIKE %s \ 
    AND CASEID IN (SELECT DISTINCT CASEID FROM TEST.NER WHERE LABEL LIKE %s \ 
    AND PHRASE LIKE %s)" 
    params=(part,condition,elem) 
    cursor.execute(query,params)