SQL Query with and without inner join [duplicate]

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Possible Duplicate:

Is it better to do an equi join in the from clause or where clause

I'm a noob in SQL,i have 2 queries:

SELECT 
    A.COLUMN1,B.COLUMN2, C.COLUMN3
FROM
     TB_ITEM A,
     TB_ITEM_CAT B,
     TB_ITEM_S开发者_如何学CUBCAT C
WHERE
     A.COLUMN1 = B.COLUMN1
     AND A.COLUMN1 = c.COLUMN1

and

SELECT 
    A.COLUMN1,B.COLUMN2, C.COLUMN3
FROM
     TB_ITEM A 
INNER JOIN TB_ITEM_CAT B on A.COLUMN1 = B.COLUMN1
INNER JOIN TB_ITEM_SUBCAT C on A.COLUMN1 = C.COLUMN1

In first query,we dont have INNER JOINS,and select from 3 tables. In the second,we have the same query with INNER JOINS,and select from 3 tables.

They are supposed to show same result? What the difference beetween these queries?

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They are semantically the same. A decent optimizer will recognize this an generate equally efficient plans. An experienced SQL coder will also recognize this ;)

Joe Celko quote, "There are at least seven ways to write a query; only two are worth using."

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The first query does have inner joins. In the FROM clause, commas are shorthand for INNER JOIN.

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well,

I think the result is the same. But, when your SQL is very large, using INNER JOIN will help you organize the query.