错误 1064：显示语法错误无法找到导致此错误的原因

Question

mysql.connector.errors.ProgrammingError: 1064 (42000): 你的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，以在第 1 行的“%s”附近使用正确的语法

代码：

 def delete_data(self):
    con = mysql.connector.connect(host="localhost", user="root", password="Satpute@223", database="stm")
    cur = con.cursor()

    cur.execute("DELETE FROM students WHERE roll_no=%s",self.Roll_No_var.get())
    con.commit()
    con.close()
    self.fetch_data()
    self.clear()

def search_data(self):
    con = mysql.connector.connect(host="localhost", user="root", password="Satpute@223", database="stm")
    cur = con.cursor()
    cur.execute("select * from students where"+str(self.search_by.get())+" like '%"+str(self.search_text.get())+"%'")
    rows = cur.fetchall()
    if len(rows) != 0:
        self.Student_table.delete(*self.Student_table.get_children())
        for row in rows:
            self.Student_table.insert('', END, values=row)

        con.commit()
    con.close()

Answer 1

你也可以试试这个：

cur.execute("DELETE FROM students WHERE roll_no=%s",
(
    self.Roll_No_var.get(),      # seperate your entries from the sql
))                               # code

--------

cur.execute("SELECT * FROM students WHERE example=%s LIKE %s ORDER BY ....",
(
     '%' + self.your_entries.get() + '%',     # there are different ways for mysql
     '%' + self.your_entries.get() + '%',     # make sure, that your table, you created matched, with your entries.
                                              #or you will get this mysql.errors
))

Answer 2

在delete_data()内部，cur.execute(...)的第二个参数应该是一个元组或列表：

cur.execute("DELETE FROM students WHERE roll_no=%s", (self.Roll_No_var.get(),))

search_data()函数内部的SQL语句中的where后面应该有一个空格：

"select * from students where "+str(self.search_by.get())+" like '%"+str(self.search_text.get())+"%'"

使用 f-string 更具可读性：

sql = f"SELECT * FROM students WHERE {self.search_by.get()} LIKE %s"
cur.execute(sql, (f"%{self.search_text.get()}%",))