Sql 如何编写查询

基于此,

我可以创建一个简单的计算字段，如下所示： 我的问题

df = pd.read_sql("select range_start, range_end  from "+table+" group by  range_start, range_end", conn)

创建此表：

Start   Stop
4385159 4499467
4175786 4352309
342426  354137
5591040 5600392

我想做的是注入一个具有diff的列，我可以这样做：

df2['Diff'] = df2['Stop'] - df2['Start']

现在我的桌子看起来像这样：

Start   End      Diff
4385159 4499467 114308
4175786 4352309 176523
342426  354137  11711

df = pd.read_sql("select (df2['Stop'] - df2['Start']) as df2['Diff'] where (df2['Stop'] - df2['Start']) < Xnumber group by (df2['Stop'] - df2['Start'])",conn)

我的问题是如何编写返回结果的查询：

df = pd.read_sql("select Diff  from "+table+" where Diff < Xnumber group by  Diff", conn)

df=pd.read_sql（“从“+表+”中选择差异，其中差异

我想我需要在jupyter（pandas）中的查询中放入一个查询。要这样做：

Start   End      Diff
4385159 4499467 114308
4175786 4352309 176523
342426  354137  11711

df = pd.read_sql("select (df2['Stop'] - df2['Start']) as df2['Diff'] where (df2['Stop'] - df2['Start']) < Xnumber group by (df2['Stop'] - df2['Start'])",conn)

df=pd.read_sql（“选择（df2['Stop']-df2['Start']）作为df2['Diff']其中（df2['Stop']-df2['Start']）

---

^这不管用，但你明白了我可能遗漏了什么，但是你能不能直接在pandas中创建新专栏，而不进行任何查询

df['Diff'] = df2['Stop'] - df2['Start']

明白了：

df6 = pd.read_sql("select (Start - Stop) as Diff from "+table+" where <condition>",conn)

df6=pd.read_sql（“选择（启动-停止）作为来自“+表+”的差异，其中，conn”）

这是可行的，但我尝试将其作为查询的一部分，以便添加条件，请参见下面的答案。但是谢谢！