Question

我正在尝试将一个查询的输出用于另一个查询，但是当我选择一个元素时，它会将输出作为，

[(8, u'O', 2, 16)]
[(8,)]
[ ]

所以第三个查询无法正常工作。我认为问题是我打印一个数字，但输出是数字列表，我试图解决它但仍然困在这里。

def OnClick(self, event):                                       
    name = event.GetEventObject().GetLabelText()
    cursor= self.conn.execute("SELECT * FROM ELEMENT where SYMBOL=='%s'"%(name))
    elements = cursor.fetchall()
    print elements
    cursor= self.conn.execute("SELECT ATOMIC_NUMBER FROM ELEMENT where SYMBOL IN ('%s')"%(name))
    numbers = cursor.fetchall()
    print numbers
    cursor= self.conn.execute("SELECT * FROM LINK where ELEMENT_NUMBER = 'numbers'")
    mnumbers = cursor.fetchall()
    print mnumbers
    #cursor= self.conn.execute("SELECT * FROM LINK where ELEMENT_NUMBER IN (SELECT ATOMIC_NUMBER FROM ELEMENT where SYMBOL IN  ('%s')%(SYMBOL))")
    #cursor= self.conn.execute("SELECT * FROM MOLECULE where MOL_NUMBER=='%d'"%(Mnumbers))
    #molecules = cursor.fetchall()
#print molecules

Answer 1

Pythons sqlite3 documentation在顶部说你不应该用你的值进行%s次替换。

将变量值引入查询的正确方法是使用SQL参数：

...execute("SELECT * FROM ELEMENT where SYMBOL==?", [name])

...execute("SELECT ATOMIC_NUMBER FROM ELEMENT where SYMBOL = ?", [name])

atomicnumber = numbers[0][0]   # extract value in first column of first row
...execute("SELECT * FROM LINK where ELEMENT_NUMBER = ?", [atomicnumber])

如何在SQLITE中将一个Query的输出用于另一个查询？

1 个答案: