从表中查找唯一列值的 SQL 查询

我们采用一个名为 Geeks 的示例表，并通过对其应用各种 SQL 查询来返回唯一的列值。

表 –极客

G_ID	FIRSTNAME	LASTNAME	JOININGDATE	DEPARTMENT
1	Mohan	Arora	7-08-2019	DBA
2	Nisha	Verma	25-03-2017	Admin
3	Vishal	Gupta	9-01-2020	DBA
4	Amita	Singh	5-12-2017	Writer
5	Vishal	Bharti	3-05-2018	Admin
6	Vinod	Diwan	19-04-2018	Review
7	Sheetal	Kumar	5-01-2017	Review
8	Geeta	Chauan	5-02-2019	Admin
9	Mona	Mishra	15-01-2018	Writer

SQL 查询从 Geeks 表中查找列部门的唯一值。

Select distinct DEPARTMENT 
from Geeks;

输出 –

DEPARTMENT
Admin
DBA
Review
Writer

SQL 查询以查找名称为“DBA”的列部门的详细信息。

Select * 
from Geeks 
where DEPARTMENT like 'DBA%';

输出 –

G_ID	FIRSTNAME	LASTNAME	JOININGDATE	DEPARTMENT
1	Mohan	Arora	7-08-2019	DBA
3	Vishal	Gupta	9-01-2020	DBA

用于查找部门“Admin”中行数的 SQL 查询。

SELECT COUNT(*) 
FROM Geeks 
WHERE DEPARTMENT = 'Admin';

输出 –

(No column name)
3