Sql include rows with 0 values

# By default, INNER JOIN excludes person_id with no appointments (NULL value, COUNT(NULL)
# returns 0). Can learn/practice more at http://sqlzoo.net/wiki/Using_Null
SELECT person.person_id, COUNT(appointment.person_id) AS "number_of_appointments"
FROM person 
  LEFT JOIN appointment ON person.person_id = appointment.person_id
GROUP BY person.person_id;

Source: stackoverflow.com

Similar codes

10 votes382 views1 answer
Oracle view dependencies
SQL
1 vote356 views1 answer
Access the postgres psql
SQL
0 vote358 views1 answer
Sql server remove enter from string
SQL
0 vote374 views1 answer
Mysql select random rows large table
SQL
0 vote362 views1 answer
The report definition has an invalid target namespace 'http://schemas.microsoft.com/SQLServer/reporting/reportdesigner'
SQL
2 votes340 views1 answer
Alter table add multiple columns postgresql
SQL
1 vote388 views2 answers
Sql insert timestamp
SQL
0 vote342 views2 answers
What is 1=2 in sql
SQL
2 votes399 views1 answer
Oracle find constraints referencing a table
SQL
0 vote364 views1 answer
Compare subqueries oracle
SQL