.


:




:

































 

 

 

 


SELECT




SELECT, , SQL. , , . . , . , ,

SELECT

: SELECT < >

FROM < > [ INTO < >

WHERE < >

GROUP BY < (), - >

HAVING < >

ORDER BY < >]

 

SELECT , .

1. .

 

SELECT , [ ], [ ]

FROM ;

 

 

DISTINCT , SELECT.

DISTINCT SELECT. SELECT , , . , , , .

 

2. , , .

 

SELECT [ ] FROM ;   SELECT DISTINCT [ ] FROM ;  

 

 

 

WHERE

WHERE SELECT (), , . , . WHERE , .

, WHERE , , . , SQL- . (join) .

FROM. () . . , . , , WHERE.

 

: WHERE ,

, . .

, : = (), >= ( ), > (, ), <= ( ), < (, ), <> ( ).

() - , , , . (/) (/).

: AND, OR, NOT.

. SQL : , , , .

 

1. , 10000 ..

 

SELECT. ,[ ],[ ]

FROM

WHERE [ ]<=10000;

 

.  
.  
.  
.  
.  
.  
.  

 

2. , 10000 ..

 

SELECT , [ ], [ ]

FROM

WHERE [ ]="" AND [ ]>10000;

 

.  
.  

 

3. .

. .

 

SELECT AS [ ], [ ], [ ] AS [ ]

FROM ,

WHERE . = .[ ];

 

 

.  
.  
.  
.  
.  
.  
.  
.  
.  
.  
.  
.  

 

 





:


: 2016-11-24; !; : 393 |


:

:

: , .
==> ...

2045 - | 1675 -


© 2015-2024 lektsii.org - -

: 0.01 .