SQL Query for specific conditions

Question

Need assistance with SQL statement for below condition. Have 3 columns in a table (TableName), Sno (unique records), Name ( there are multiple records that can have same name) , Condition (True,False) . Need to extract All records if the last record true only.

Have tried below query

select Sno(Max),Name,Condition 
from TableName 
where Conditon = 'True' 
group by Name,Conditon;

Expected: If last record (SNo (Max)) has value = true (condition column) then return this record, else no records displayed.

Actual: All records are displayed including true and false condition

Answer 1

I think you're looking for that:

SELECT Sno, Name, Condition 
FROM TableName 
WHERE Conditon = 'True' AND Sno=(SELECT MAX(Sno) FROM TableName);

Beware of types: if 'Condition' column is Boolean WHERE clause should be

WHERE Condition IS TRUE AND ... 

Answer 2

I think this is what you are looking for.
If table is like this:

[It's recommended to use tinyint(1) as Boolean in MySQL.]

You can use this query:

SELECT a.*
FROM `TableName` a
LEFT JOIN `TableName` b ON(a.`Sno` < b.`Sno`
                           AND a.`Name` = b.`Name`)
WHERE a.`Conditon` = 1
  AND b.`Sno` IS NULL

to get this result:

This way will work more effective than using an inner sub-query. Especially in large tables.

Answer 3

Could be use a where exist on a subquery for condition TRUE and Sno = max(Sno)

select  * 
from TableName 
where exist (
  select  * 
  from TableName 
  where  Condition = 'True'  
  and  Sno = (
  select  max(Sno) 
  from TableName 
  )
)

Answer 4

SELECT * 
FROM   tablename 
WHERE  sno IN (SELECT Sno(max) 
               FROM   tablename 
               GROUP  BY NAME) 
       AND condition = 'true'