Python：如何使用psycopg2將字符串傳遞到Postgress命令

Question

我有一個問題，在python中爲postgresql傳遞字符串。特別是我有以下腳本完美的作品：

y = 'test' 
for i in un: 
    crs = conn.cursor() 
    query = """ 
     select * 
     FROM test 
     WHERE test.vin_id = %s 
    ;""" 
    s_id = i 
    crs.execute(query,[s_id]) 
    s_out = crs.fetchall() 

，但如果我改變test與可變y它給了我一個錯誤。

for i in un: 
    crs = conn.cursor() 
    query = """ 
     select * 
     FROM %s 
     WHERE %s.vin_id = %s 
    ;""" 
    s_id = i 
    crs.execute(query,[y,y,s_id]) 
    s_out = crs.fetchall() 

ProgrammingError: syntax error at or near "'test'" 
LINE 3:   FROM 'test' 

Answer 1

您可以使用AsIs：

from psycopg2.extensions import AsIs 
for i in un: 
    crs = conn.cursor() 
    query = """ 
     select * 
     FROM %s 
     WHERE %s.vin_id = %s 
    ;""" 
    s_id = i 
    crs.execute(query,[AsIs(y),AsIs(y),s_id]) 
    s_out = crs.fetchall() 

Answer 2

遺憾的是它不工作，我有同樣的問題，當我試圖把句子中間，比如：

query1 = """ 
SELECT * 
FROM test1 
WHERE %s LIKE '%' || vin_id || '%' 
;"""  
crs1 = conn.cursor() 
crs1.execute(query1, [s_id])