Bi SQL alias

Alias

Alias, Alias means . stay SQL Server In the database of , We can use AS Specify aliases for tables or columns or queries .

Please don't ignore this ,AS It's especially useful at times , It can be said that the frequency of use is very high .

Basic grammar

Table grammar 1：

SELECT  Column name (*) FROM  surface  AS  Alias 

Column syntax 1：

SELECT  Column name  AS  Alias  FROM  surface 

Using examples

Case data ：

In the database of white tea machine , There is a name “TEST” The database of , There is a name “ Product list ” The dimension table and the name are “ Sales details ” The fact sheet of .

Example 1：

stay PowerBI in , take “ Product list ” Medium [ Name of commodity ] Name it “Product”.

SELECT [ Name of commodity ] AS Product FROM [ Product list ]

give the result as follows ：

Example 2：

stay PowerBI in , take “ Sales details ” Name it “Fact_Detail”, Again from “Fact_Detail” Table acquisition [ sales volumes ] Aggregate value of .

give the result as follows ：

AS In the first two examples, it does not reflect its value , We can look at it from the perspective of the result set .

notes ： Result set refers to the result set after query .

Example 3：

stay PowerBI in , quote [ Product list ] All the information about , And calculate according to the correlation [ Name of commodity ] Corresponding [ Sales details ] In the table [ sales volumes ] Summary .

SELECT [ Product list ].* , SUM([ Sales details ].[ sales volumes ]) AS Quantity
FROM [ Product list ]
LEFT JOIN [ Sales details ]
ON [ Product list ].[ Name of commodity ]=[ Sales details ].[ Name of commodity ]
GROUP BY  [ Product list ].[ Name of commodity ],[ Product list ].[ Item number ],[ Product list ].[ Classification of goods ],[ Product list ].[ The sale price ],[ Product list ].[ cost ]
ORDER BY  Quantity DESC

give the result as follows ：

Of course , We can also use the following expression .

SELECT [ Product list ].*, SUMARRIZE.Quantity
FROM [ Product list ]
LEFT JOIN 
    (SELECT [ Sales details ].[ Name of commodity ] ,
         SUM([ Sales details ].[ sales volumes ]) AS Quantity
    FROM [ Sales details ]
    GROUP BY  [ Sales details ].[ Name of commodity ]) AS SUMARRIZE
ON [ Product list ].[ Name of commodity ]=SUMARRIZE.[ Name of commodity ]
ORDER BY  Quantity DESC

give the result as follows ：

This is white tea , One PowerBI Beginners .