9
: SQL .
: SQL- , , SQL.
SELECT
SELECT () : [UNION [ALL] ]... [ORDER BY {[.] | __SELECT} [[ASC] | DESC] [,{[.] | __SELECT} [[ASC] | DESC]]...;
(UNION) (ORDER BY) , "". - ASC (ASCending) DESC (DESCending), ASC.
( )
SELECT () ( ) ()
FROM () ,
WHERE ()
GROUP BY ( ) , , SELECT SQL- SUM (), COUNT (), MIN ( ), MAX ( ) AVG ( )
HAVING () ,
SELECT [[ALL] | DISTINCT]{ * | _SELECT [,_SELECT]...} FROM {_ | } [] [,{_ | } []]... [WHERE ] [GROUP BY [HAVING ]];
_SELECT - : [.]* | | SQL_ | _
: [.] | () | |
({[ [+] | - ] { | _} [ + | - | * | ** ]}...)
SQL_ : {SUM|AVG|MIN|MAX|COUNT} ([[ALL]|DISTINCT][.]) {SUM|AVG|MIN|MAX|COUNT} ([ALL] ) COUNT(*)
WHERE : WHERE [NOT] WHERE_ [[AND|OR][NOT] WHERE_]...
WHERE_ : { = | <> | < | <= | > | >= } { | () } _1 [NOT] BETWEEN _2 AND _3 [NOT] IN { ( [,]...) | () } IS [NOT] NULL [.] [NOT] LIKE '_' [ESCAPE ''] EXISTS ()
(= | <> | < | <= | > | >=) WHERE BETWEEN (), LIKE ( ), IN (), IS NULL ( ) EXISTS (), NOT (). , :
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OR - OR ;
AND NOT - ;
OR NOT - ,
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- , , . , , , ASCII. , , , .
, GROUP BY
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GROUP BY , , GROUP BY. , SELECT, (, ..).
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, :
{ = | <> | < | <= | > | >= } { | ()
| SQL_ }
{_1 | SQL__1} [NOT] BETWEEN
{_2 | SQL__2} AND {_3 | SQL__3}
{ | SQL_} [NOT] IN { ( [,]...)
| () }
{ | SQL_} IS [NOT] NULL
[.] [NOT] LIKE '_' [ESCAPE '']
EXISTS ()
1. ( , , ).
WHERE
Like , *
SELECT
FROM
WHERE Like '**' Or Like '**' Or Like '**';
. 3-11, .
2. ( 1.02.04 31.03.04). , Between And ( )
SELECT , , ,
FROM
WHERE Between #2-1-2004# And #3-31-2004#;
. 4-1.
1. (, ). ( ) .
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SELECT DISTINCT . AS ,
FROM ,
WHERE . = .;
. 4-2.
2.
( , ). . .
: ( ) ( ) ( () ). , .
SELECT , , [] + [()] AS
FROM ,
WHERE . = .
ORDER BY ;
SQL-
SQL (SQL-). COUNT(*) , :
COUNT ,
SUM ,
AVG ,
MAX ,
MIN ,
SUM AVG .
, - , , , () . , , , SQL- ( SQL- ). SQL- .
, COUNT(*), DISTINCT (), , , .
COUNT(*) ( ).
1.
SELECT Count(*)AS
FROM ;
GROUP BY, _SELECT SQL- , . , , SQL-.
2. (=8), ,
SELECT Sum() AS , Count() AS
FROM
WHERE = 8;
3.
SELECT , Sum([]*[]) AS
FROM
GROUP BY ;
GROUP BY ( ) FROM , , GROUP BY. , = 25.03.03, = 02.01.04 .. (. 3-6). SELECT. , .. , GROUP BY, , , , SQL-, (, ).
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1. SELECT ?
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3. ?
4. SQL ?
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