我已经在PL SQL中创建了此查询，在这里我必须检查一次操作需要花费多少时间。
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col EVENT for a35
col SQL_ID for a13
col ET for 9999
col mymac for a15
col username for a12
SELECT MAX(a.last_call_et)
FROM gv\\$session a,gv\\$sqlarea c
where c.address= a.sql_address
and c.hash_value = a.sql_hash_value
and a.username='XXXX'
and a.last_call_et>600
order by a.last_call_et;
我想以某种方式修改此查询，以显示从结果中获得多少行。例如，如果我的查询结果将有两行，我想显示“ 2”
我认为您可以将count聚合函数与现有的max聚合函数一起使用，如下所示：
SELECT MAX(a.last_call_et),count(1) as total_rows --<-- this
FROM gv\\$session a,gv\\$sqlarea c
where c.address= a.sql_address
and c.hash_value = a.sql_hash_value
and a.username='XXXX'
and a.last_call_et>600
-- order by a.last_call_et; this order by is of no use
干杯！
,由于它是SQL * Plus，因此只需进行一点格式化即可。例如：
SQL> break on report
SQL> compute count of ename on report
SQL>
SQL> select ename from emp where deptno = 10;
ENAME
----------
CLARK
KING
MILLER
----------
3
SQL>