Microsoft SQL Server 内部联接
示例
Innerjoin根据一个或多个条件（使用ON关键字指定）仅返回在两个表中匹配/存在的记录/行。这是最常见的联接类型。的一般语法为innerjoin：
SELECT * FROM table_1 INNER JOIN table_2 ON table_1.column_name = table_2.column_name
也可以简化为JOIN：
SELECT * FROM table_1 JOIN table_2 ON table_1.column_name = table_2.column_name
例
/* Sample data. */
DECLARE @Animal table (
AnimalId Int IDENTITY,
Animal Varchar(20)
);
DECLARE @AnimalSound table (
AnimalSoundId Int IDENTITY,
AnimalId Int,
Sound Varchar(20)
);
INSERT INTO @Animal (Animal) VALUES ('Dog');
INSERT INTO @Animal (Animal) VALUES ('Cat');
INSERT INTO @Animal (Animal) VALUES ('Elephant');
INSERT INTO @AnimalSound (AnimalId, Sound) VALUES (1, 'Barks');
INSERT INTO @AnimalSound (AnimalId, Sound) VALUES (2, 'Meows');
INSERT INTO @AnimalSound (AnimalId, Sound) VALUES (3, 'Trumpets');
/* Sample data prepared. */
SELECT
*
FROM
@Animal
JOIN @AnimalSound
ON @Animal.AnimalId = @AnimalSound.AnimalId;AnimalId Animal AnimalSoundId AnimalId Sound ----------- -------------------- ------------- ----------- -------------------- 1 Dog 1 1 Barks 2 Cat 2 2 Meows 3 Elephant 3 3 Trumpets
将内部联接与左侧外部联接一起使用（不存在替代）
该查询将返回表1中的数据，其中与带有条件键的table2匹配的字段和与带条件键的Table2进行比较时不在表1中的数据
select *
from Table1 t1
inner join Table2 t2 on t1.ID_Column =t2.ID_Column
left join Table3 t3 on t1.ID_Column =t3.ID_Column
wheret2.column_name= column_value
andt3.ID_Columnis null
order by t1.column_name;