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I will explain GROUP BY Statement in Oracle SQL in this post of Oracle SQL Tutorial series.
Read the previous post of this tutorial series before this.
IN and BETWEEN Operator in Oracle SQL | Oracle SQL Tutorials -15
GROUP BY Statement
GROUP BY statement is very popular in Oracle SQL. You can group specific or all rows which have same values into summary rows.
Aggregate functions (MAX, MIN, SUM, AVG,COUNT) are often used in the Group by statements.
GROUP BY Syntax
GROUP BY syntax is as follows.
SELECT column1,column2 FROM table_name WHERE condition GROUP BY column1,column2;
SELECT column1,column2 FROM table_name WHERE condition GROUP BY column1,column2
ORDER BY column_name(s);
SELECT column_name(s) FROM table_name WHERE condition GROUP BY column_name(s) ORDER BY column_name(s);
Group by examples are as follows.
SQL> select first_name,last_name,salary from hr.employees where department_id in (20,30,40) group by first_name,last_name,salary; FIRST_NAME LAST_NAME SALARY -------------------- ------------------------- ---------- Alexander Khoo 4100 Pat Fay 7000 Karen Colmenares 3500 Michael Hartstein 14000 Guy Himuro 3600 Den Raphaely 12000 Shelli Baida 3900 Sigal Tobias 3800 Susan Mavris 7500 9 rows selected. SQL> select salary,count(*) from hr.employees where department_id in (20,30,40,50,60,70) group by salary; SALARY COUNT(*) ---------- ---------- 5200 2 12000 1 9000 1 4000 2 5000 1 14000 1 11000 1 10000 1 3900 3 3400 2 4600 2 SALARY COUNT(*) ---------- ---------- 4500 1 3800 4 3500 6 4100 4 4400 1 4800 1 8900 1 7500 2 4200 4 4300 2 4900 1 SALARY COUNT(*) ---------- ---------- 3600 4 3700 2 5800 2 6800 1 3200 2 3100 1 5100 1 7000 2 9200 1 31 rows selected. SQL>
SQL> select department_id,sum(salary) from hr.employees group by department_id; DEPARTMENT_ID SUM(SALARY) ------------- ----------- 100 57608 30 30900 8000 90 46000 20 21000 70 11000 110 22308 50 201400 80 338500 40 7500 60 33800 DEPARTMENT_ID SUM(SALARY) ------------- ----------- 10 5400 12 rows selected. SQL>
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