通过sql查询emp表(主键emp_id)时,可统计表中记录总数的语句是()
A.select count(all) from emp;
B.select count(emp_id) from emp;
C.select count(*) from emp;
D.select count(1) from emp;
A.select count(all) from emp;
B.select count(emp_id) from emp;
C.select count(*) from emp;
D.select count(1) from emp;
第2题
A.Between#1995-01-01#And#1995-12-31#
B.Between“1995-01-01”And“1995-12-31”
C.Between“1995.01.01”And“1995.12.31”
D.#1995-01-01#And#1995-12-31#
第3题
第6题
A.SELECT*FROM教师FORLEFT(职工号,3)="110"
B.ALTERTABLE教师ALTER职工号SETCHECKLEFT(职工号,3)="110"
C.SELECT*FROM教师WHERELEFT(职工号,3)="110"
D.CHANGETABLE教师ALTER职工号SETCHECKOCCURS(职工号,3)="110"
第9题
A.使用mapjoinhint:select/*+mapjoin(t2)*/region_name,sum(order_amt)amtfromordert1joinregiont2ont1.region_id=t2.region_id;
B.使用mapjoinhint:select/*+mapjoin(t1)*/region_name,sum(order_amt)amtfromordert1joinregiont2ont1.region_id=t2.region_id
C.调整两张表的位置:selectregion_name,sum(order_amt)amtfromregiont1joint2ont1.region_id=t2.region_id
D.减小SQL的splitsize,增加计算资源