Oracle+mybatis sql报ORA-00923: 未找到要求的 FROM 关键字

select trunc to_char(ordoprtime, 'hh24') periodtime,
max(consumingtime) maxcosttime,
min(consumingtime) mincosttime,
avg(consumingtime) costtime
from sync_cooperator
where ordoprtime between sysdate - 200 and sysdate
and business = '00'
and status = '01'
group by trunc to_char(ordoprtime, 'hh24');
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控制台报:
Cause: java.sql.SQLException: ORA-00923: 未找到要求的 FROM 关键字

; bad SQL grammar []; nested exception is java.sql.SQLException: ORA-00923: 未找到要求的 FROM 关键字
] with root cause
java.sql.SQLException: ORA-00923: 未找到要求的 FROM 关键字

at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:331)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:288)
at oracle.jdbc.driver.T4C8Oall.receive(T4C8Oall.java:745)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:219)
at oracle.jdbc.driver.T4CPreparedStatement.executeForDescribe(T4CPreparedStatement.java:813)

我是刚入行的菜鸟,请问各位大神,这里那里有异常请指教.

select trunc(to_char(ordoprtime, 'hh24')) periodtime, --这个地方
       max(consumingtime) maxcosttime,
       min(consumingtime) mincosttime,
       avg(consumingtime) costtime
  from sync_cooperator
 where ordoprtime between sysdate - 200 and sysdate
   and business = '00'
   and status = '01'
 group by trunc(to_char(ordoprtime, 'hh24')); --这个地方上边标注的2个地方，自己看看差在哪里吧，这些东西你先在oracle里执行无误了再放到代码里，别sql还没运行成功就扔进去

b = '数学' then c else null end as a2这句开头也要case when