***************   Case 1   ***************

SQL: explain extended select * from t1 order by c1,c2 limit 100; 

=================================
|ID|OPERATOR|NAME|EST. ROWS|COST|
---------------------------------
|0 |VALUES  |    |0        |0   |
=================================

Outputs & filters: 
-------------------------------------
  0 - output(nil), filter(nil)

*************** Case 1(end)  ************** 

***************   Case 2   ***************

SQL: explain extended select c2, sum(c1) from t1 group by c2; 

=================================
|ID|OPERATOR|NAME|EST. ROWS|COST|
---------------------------------
|0 |VALUES  |    |0        |0   |
=================================

Outputs & filters: 
-------------------------------------
  0 - output(nil), filter(nil)

*************** Case 2(end)  ************** 

***************   Case 3   ***************

SQL: explain extended select t1.c1 from t1,t2,t3, t1 tt where t1.c1=t3.c1 and t1.c2=tt.c2 and t1.c1+t2.c1=tt.c1; 

=================================
|ID|OPERATOR|NAME|EST. ROWS|COST|
---------------------------------
|0 |VALUES  |    |0        |0   |
=================================

Outputs & filters: 
-------------------------------------
  0 - output(nil), filter(nil)

*************** Case 3(end)  ************** 

***************   Case 4   ***************

SQL: explain extended select t1.c1 from t1, (select * from t2 where c2>1 order by c1 limit 10) as t where t1.c1=t.c1; 

=================================
|ID|OPERATOR|NAME|EST. ROWS|COST|
---------------------------------
|0 |VALUES  |    |0        |0   |
=================================

Outputs & filters: 
-------------------------------------
  0 - output(nil), filter(nil)

*************** Case 4(end)  ************** 

***************   Case 5   ***************

SQL: explain extended select t1.c1 from t1 left join t2 t on t1.c1=t.c1,t2,t3, t1 tt where t1.c1=t3.c1 and t1.c2=tt.c2 and t1.c1+t2.c1=tt.c1; 

=================================
|ID|OPERATOR|NAME|EST. ROWS|COST|
---------------------------------
|0 |VALUES  |    |0        |0   |
=================================

Outputs & filters: 
-------------------------------------
  0 - output(nil), filter(nil)

*************** Case 5(end)  **************