# 1194. Tournament Winners
with t as (select group_id , player,sum(score) as score
from (select p.group_id ,first_player as player, first_score as score from Matches m join Players p on m.first_player=p.player_id
select p.group_id,second_player as player, second_score as score from Matches m join Players p on m.second_player=p.player_id
) as tb
group by player
order by group_id, score desc,player)
select group_id,player as player_id
group by group_id
order by player
If we want to display the results of the two select statements as a whole, we need to use the ‘UNION and UNION ALL keywords.
The function of UNION is to combine multiple results and display them.
SELECT * FROM table_a
SELECT * FROM table_b
The UNION and…
Lemmatization and Stemming are both preprocessing stages in natural language processing(NLP). The purpose of using Lemmatization and Stemming is to reduce the impact of words on processing accuracy due to tense, singular, plural, and inflection.
Take Lemmatization as an example. In English, ‘good’, ‘better’, and ‘best’ are three words, but…
The two are all data preprocessing methods:
fit(): calculates the parameters μ and σ and saves them as internal objects. In short, it is to find the mean, variance, maximum, and minimum of the training set X’s featured. It can be understood as a training process.
transform(): using parameters calculated…
False: If subjects are randomly assigned to treatments, conclusions can be generalized to the population.
Classify a study as observational or experimental, and determine whether the study’s results can be generalized to the population and whether they suggest correlation or causation.
If random sampling has been employed in data collection…
When I want to build connections between database and Python programs with SQLAlchemy on Google Colab, it occurs errors saying: (mysql.connector.errors.InterfaceError) 2003: Can’t connect to MySQL server on ‘localhost:3306’ (111 Connection refused) and Can’t connect to MySQL server on ‘localhost:3306’ [Errno 99] Cannot assign requested address.
Here’s my solution. It…
MySQL verison: 8.0.22
Step1. Stop MySQL Server
Make sure the status of MySQL Server located in macOS System Preferences Panel is in red(means stopped). If it is in green(means running)，you must top it by clicking the ‘Stop MySQL Server’ button.
*If Stop MySQL Server has no response, try: