我在参数化中显然做错了,但不确定正确的语法是什么。
期望,但不起作用:在IN的多个条件
data = ['lol', 'hi']
query = """ select word, count(1) from table where word in (%(ids)s) group by 1"""
pandas.read_sql_query(sql=query, con=db_engine, params={'ids':data})
输出:
InternalError: (pymysql.err.InternalError) (1241, 'Operand should contain 1 column(s)') [SQL: "select word, count(1) from table where word in (%(ids)s) group by 1 "] [parameters: {'ids': ('lol', 'hi')}]
不合适,但有效:IN中的单一条件(长度为1的列表没问题)
data = ['lol']
query = """ select word, count(1) from table where word in (%(ids)s) group by 1"""
pandas.read_sql_query(sql=query, con=db_engine, params={'ids':data})
删除占位符周围的括号。因为查询是在pymysql完成参数替换后将word
与(('lol', 'hi'))
进行比较,或者换句话说是对元组的标量。长度为1的列表很好,因为结果是(('hi'))
,并且SQL在比较时实际上将标量word
视为1列行,这可能是稍微不明显的错误提示。
所以查询应该如下所示:
query = """
select word, count(1)
from table
where word in %(ids)s
group by 1
"""