So this is the truth table:
In_1 In_2 In_3 Out
0 0 0 1
0 0 1 1
0 1 0 1
0 1 1 1
1 0 0 1
1 0 1 1
1 1 0 1
1 1 1 1
How do I create a circuit that matches this truth table?
Here is what I have tried, but this did not work:
Please help would be appreciated.
You just need to connect the output to a constant logic 1, which is usually just the power supply voltage. This is a trivial logic function and requires no gates to implement.
The solution is to apply Kmap. We will be ending up with an equation that will be similar to
but this is not the reduced form. If we try to reduce this equation we will end up with 1.
Check this tool for better understanding.
https://www.boolean-algebra.com/kmap/
So this is the truth table
In_1 In_2 In_3 Out
0 0 0 0
0 0 1 1
0 1 0 1
0 1 1 1
1 0 0 1
1 0 1 1
1 1 0 1
1 1 1 0
I would like to create a circuit based on this truth table.
This is what I have tried, but failed
A Karnaugh map as suggested by paddy, will give you a set of minterms which fulfil the expression. That is the classical way to tackle such problems.
By inspection of the truth-table you can convince yourself, that the output is true whenever In_1 is unequal In_3 or In_1 is unequal In_2:
f = (In_1 xor In_2) or (In_1 xor In_3)
I want to ask if it is possible to do a query and have a result like this? The more difficult part is to have a half-split column within the same row.
M stands for Male and F stands for Female for those who are wondering.
Teacher Class Level Name 7 8 9 10 11
M F M F M F M F M F
Mr A Class 1 Ant 0 0 3 9 0 1 0 0 0 0
Ms B Class 1 Bumble Bee 0 0 11 5 1 0 0 0 0 0
Mrs C Class 2 Cat 0 0 0 1 7 1 0 0 0 0
Mdm D Class 3 Dog 0 0 0 0 0 0 7 0 1 0
I have attached the same table but in excel so it's easier to see. It will be good if this can be done in pure sql query.
Thank you in advance to those who help in any way.
The closest result you could get solely using SQL would be to have a table returned with the following column headers:
Teacher Name, Class Level, Name, 7_M, 7_F,8_M, 8_F,9_M, 9_F,10_M, 10_F,11_M, 11_F.
Now, to display those X_M and X_F column as "half-split", you would have to do it outside SQL (EDIT: For the reasons Radim mentioned in his comment).
I'm trying to write a query to process a single table that looks like this:
record_id item_id part_id part_length
----------- ------- -------- ------------
1 0 0 123.12
2 0 0 123.09
3 0 1 231.24
4 0 1 239.14
5 1 0 45.91
6 1 0 46.12
7 1 1 62.24
8 1 1 59.40
which is basically a table of inaccurate length measurements of some parts of some items recorded multiple times (not twice, actually each part has 100s of measurements). With a single select, I want to get a result like this:
record_id item_id part_id unit part_length_ratio
----------- ------- -------- ----- ----------------
1 0 0 1 123.12 / 231.24
2 0 0 1 123.09 / 239.14
3 0 1 0 231.24 / 123.12
4 0 1 0 239.14 / 123.09
5 1 0 1 45.91 / 62.24
6 1 0 1 46.12 / 59.40
7 1 1 0 62.24 / 45.91
8 1 1 0 59.40 / 46.12
which is basically selecting each part of an item as the unit and calculates the ratio of the length of other parts of the same item to this unit while matching the measurement times. I wrote a script which computes this kind of table but would like to do it with sql. I can understand if you fail to understand the question :)
for each item i
for each part unit of i
for each part other of i
if unit != other
print i.id other.part_id unit.part_id other.length / unit.length
As I said in a comment, tables are unordered sets: there is no first or second row...
... unless if you want to use the id column to explicitly order the rows.
However, can you guarantee that there will always be (exactly) two samples for each case and that the "lower ID" always match the first sample? This appears to be quite fragile as in real-life, there will probably have cases where a test will be performed twice or a test will be missing or done "late". Not mentioning concurrent access to your DB.
Can't you simply add a "sample number" column?
I have a big table with 300,000 records. This table has a integer value called "velocity" and it`s value is from 0 to 100.
In the firsts records, the value is 0 and I want to remove. I want to remove from the query, the records where the velocity field repeats more than 10 times. For example:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 3 5 10 12 13 15 20 30 20 15 10 8 5 2 1 0 0 0 0 4 5 10 20...
[-------remove this-----------].......................................................................[---------] <- do not remove this
Thanks
The easiest way to do this is with a loop.
You can write a stored procedure that iterates through the records, or you might do it outside of the database. I'd do it like that if this needs to be done once. If this is a continuous process, it's better to make sure that the extra data is just not inserted into the database in the first place.
Anyway, if you insist on doing this in pure SQL, without stored procedures with loops, you can use a query like this:
set #groupnum=0;
select
GroupNum,
count(*) as RecsInGroup
from
(
select
t1.id as Id,
t1.velocity as velocity1,
t2.velocity as velocity2,
if(t1.velocity<>t2.velocity,#groupnum:=#groupnum+1,#groupnum) as GroupNum
from
VelocityTable as t1
join
VelocityTable as t2
on
t1.id=t2.id-1
) as groups
group by
GroupNum
having RecsInGroup>10
What happens here?
Step 1
The inner query just selects all records in your table, but splits the data in sequential groups.
So, using your example, it does this:
velocity : 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 3 5 10 12 13 15 20 30 20 15 10 8 5 2 1 0 0 0 0 4 5 10 20
Groupnum : 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 18 18 18 19 20 21 22
It does that by joining the table to itself, by linking subsequent records in the table. Every time the left and right velocity are different, the GroupNum is increased. Otherwise it's left unchanged.
Step 2
The result if the query is wrapped in an outer query, and grouped by GroupNum. Again, using your example it would result in this:
GroupNum,RecsInGroup
0,15 // !!
1,1
2,1
3,1
4,1
5,1
6,1
7,1
8,1
9,1
10,1
11,1
12,1
13,1
14,1
15,1
16,1
17,1
18,4 // !!
19,1
20,1
21,1
By Adding the having RecsInGroup>10 clause, the result becomes this:
GroupNum,RecsInGroup
0,15
Now, with this list of GroupNum's you can delete records.
Step 3
With the query above you have:
A list of all your records, with an added GroupNum column.
The list of GroupNum's that need to be removed.
Deleting the records should be easy at this point.
I'd just rip through the records sequentially, with a variable sized window that expands and contracts to comprehend identical values. Whenever the size is >= 10 when the value changes, delete the rows using the primary keys.
You can put BEGIN TRAN and COMMIT TRAN at the beginning and end of the DELETE statements to make things reasonably efficient.
thank you very much. I'm allmost there, but i tried it with a mySQL View as table source and it's not working (unkown table xxx). I can't use the whole table because it's have more than 19 millions records, I just need the record from a specific day, vehicle plate and city.