SQL Daily Practice — Day 14
Hello, Connections, Data Professionals and SQL Enthusiasts.
Here comes #day14 of our SQL daily practice on SQL-practice-dot-com.
Follow Olawale Ahmed Alamu and #sqldailyupdates for #day1 to #day13 and daily updates.
Today, we are looking at SQL COUNT(column_name) function.
SQL COUNT(column_name) function is used to get the total number of records in a column that is not NULL.
QUESTION: Show the total number of admissions for patient_id: 579
PROBLEM ANALYSIS: We are expected to output the total count of when patient_id: 579 was admitted.
The admissions table has the following columns:
patient_id (INT),
admission_date (DATE),
discharge_date (DATE),
diagnosis (TEXT),
attending_physician_id (INT),
pk_admissions
SOLUTION: We write a SELECT COUNT(patient_id) with a WHERE clause to filter for only patient_id: 579.
SQL CODE:
— — — — — —
SELECT
patient_id,
COUNT(patient_id) AS total_admissions
FROM admissions
WHERE patient_id = 579
— — — — — —
A screenshot of the SQL Script and output is attached in the image below:
