SQL 排序

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1，使用ORDERBY子句：

可以按一个或多个属性列排序

升序：ASC；降序：DESC；缺省值为升序

2，当排序列含空值时

ASC：排序列为空值的元组最后显示

DESC：排序列为空值的元组最先显示

eg:

SQL>select * from customers order by dob;

CUSTOMER_IDFIRST_NAME LAST_NAME DOB PHONE

--------------------- ---------- -------------- ------------

1 John Brown 01-1月 -65 800-555-1211

2 Cynthia Green 05-2月 -68 800-555-1212

5 Doreen Blue 20-5月 -70

3 Steve White 16-3月 -71 800-555-1213

4 Gail Black 800-555-1214

SQL>select * from customers order by dob asc;

CUSTOMER_IDFIRST_NAME LAST_NAME DOB PHONE

--------------------- ---------- -------------- ------------

1 John Brown 01-1月 -65 800-555-1211

2 Cynthia Green 05-2月 -68 800-555-1212

5 Doreen Blue 20-5月 -70

3 Steve White 16-3月 -71 800-555-1213

4 Gail Black 800-555-1214

SQL>select * from customers order by dob desc;

CUSTOMER_IDFIRST_NAME LAST_NAME DOB PHONE

--------------------- ---------- -------------- ------------

4 Gail Black 800-555-1214

3 Steve White 16-3月 -71 800-555-1213

5 Doreen Blue 20-5月 -70

2 Cynthia Green 05-2月 -68 800-555-1212

1 John Brown 01-1月 -65 800-555-1211

SQL>select * from customers order by last_name desc;

CUSTOMER_IDFIRST_NAME LAST_NAME DOB PHONE

--------------------- ---------- -------------- ------------

3 Steve White 16-3月 -71 800-555-1213

2 Cynthia Green 05-2月 -68 800-555-1212

1 John Brown 01-1月 -65 800-555-1211

5 Doreen Blue 20-5月 -70

4 Gail Black 800-555-1214

SQL>select * from customers order by last_name asc;

CUSTOMER_IDFIRST_NAME LAST_NAME DOB PHONE

--------------------- ---------- -------------- ------------

4 Gail Black 800-555-1214

5 Doreen Blue 20-5月 -70

1 John Brown 01-1月 -65 800-555-1211

2 Cynthia Green 05-2月 -68 800-555-1212

3 Steve White 16-3月 -71 800-555-1213

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SQL&nbsp;排序

SQL 排序