sql - Is there any difference between these two SELECT statements? -

One of my friends told me about Statement 2 , but in this way I have not yet been able to < Strong> Statement 1 .

• Is there any difference between these two SELECT statements?

• If so, what is it?

Description 1:

  Selection 1 to Table 1;  

Select Details 2:

  Select Table1. Call 1 from Table1;  

There is no difference at all

But when you have:

  Select Table 1 Table 1 from INNER to Table 2 ON (Table1.id = Table2.ref_id);  

The second statement is probably a better idea because it will remove any ambiguity for the Col1. In that case the call can be a field in Table 1 or Table 2.

In fact if there is a field named "Call 1" in Table 2, then you have to use the second statement.