SQLite Exercise: Get the department name and number of employees in the department
Write a query to get the department name and number of employees in the department.
Sample table: employees
+-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+ | EMPLOYEE_ID | FIRST_NAME | LAST_NAME | EMAIL | PHONE_NUMBER | HIRE_DATE | JOB_ID | SALARY | COMMISSION_PCT | MANAGER_ID | DEPARTMENT_ID | +-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+ | 100 | Steven | King | SKING | 515.123.4567 | 1987-06-17 | AD_PRES | 24000.00 | 0.00 | 0 | 90 | | 101 | Neena | Kochhar | NKOCHHAR | 515.123.4568 | 1987-06-18 | AD_VP | 17000.00 | 0.00 | 100 | 90 | | 102 | Lex | De Haan | LDEHAAN | 515.123.4569 | 1987-06-19 | AD_VP | 17000.00 | 0.00 | 100 | 90 | | 103 | Alexander | Hunold | AHUNOLD | 590.423.4567 | 1987-06-20 | IT_PROG | 9000.00 | 0.00 | 102 | 60 | | 104 | Bruce | Ernst | BERNST | 590.423.4568 | 1987-06-21 | IT_PROG | 6000.00 | 0.00 | 103 | 60 | | 105 | David | Austin | DAUSTIN | 590.423.4569 | 1987-06-22 | IT_PROG | 4800.00 | 0.00 | 103 | 60 | | 106 | Valli | Pataballa | VPATABAL | 590.423.4560 | 1987-06-23 | IT_PROG | 4800.00 | 0.00 | 103 | 60 | | 107 | Diana | Lorentz | DLORENTZ | 590.423.5567 | 1987-06-24 | IT_PROG | 4200.00 | 0.00 | 103 | 60 | | 108 | Nancy | Greenberg | NGREENBE | 515.124.4569 | 1987-06-25 | FI_MGR | 12000.00 | 0.00 | 101 | 100 | | 109 | Daniel | Faviet | DFAVIET | 515.124.4169 | 1987-06-26 | FI_ACCOUNT | 9000.00 | 0.00 | 108 | 100 | | 110 | John | Chen | JCHEN | 515.124.4269 | 1987-06-27 | FI_ACCOUNT | 8200.00 | 0.00 | 108 | 100 | | 111 | Ismael | Sciarra | ISCIARRA | 515.124.4369 | 1987-06-28 | FI_ACCOUNT | 7700.00 | 0.00 | 108 | 100 | | 112 | Jose Manuel | Urman | JMURMAN | 515.124.4469 | 1987-06-29 | FI_ACCOUNT | 7800.00 | 0.00 | 108 | 100 | | 113 | Luis | Popp | LPOPP | 515.124.4567 | 1987-06-30 | FI_ACCOUNT | 6900.00 | 0.00 | 108 | 100 | | 114 | Den | Raphaely | DRAPHEAL | 515.127.4561 | 1987-07-01 | PU_MAN | 11000.00 | 0.00 | 100 | 30 | | 115 | Alexander | Khoo | AKHOO | 515.127.4562 | 1987-07-02 | PU_CLERK | 3100.00 | 0.00 | 114 | 30 | | 116 | Shelli | Baida | SBAIDA | 515.127.4563 | 1987-07-03 | PU_CLERK | 2900.00 | 0.00 | 114 | 30 | | 117 | Sigal | Tobias | STOBIAS | 515.127.4564 | 1987-07-04 | PU_CLERK | 2800.00 | 0.00 | 114 | 30 | | 118 | Guy | Himuro | GHIMURO | 515.127.4565 | 1987-07-05 | PU_CLERK | 2600.00 | 0.00 | 114 | 30 | | 119 | Karen | Colmenares | KCOLMENA | 515.127.4566 | 1987-07-06 | PU_CLERK | 2500.00 | 0.00 | 114 | 30 | | 120 | Matthew | Weiss | MWEISS | 650.123.1234 | 1987-07-07 | ST_MAN | 8000.00 | 0.00 | 100 | 50 | | 121 | Adam | Fripp | AFRIPP | 650.123.2234 | 1987-07-08 | ST_MAN | 8200.00 | 0.00 | 100 | 50 | | 122 | Payam | Kaufling | PKAUFLIN | 650.123.3234 | 1987-07-09 | ST_MAN | 7900.00 | 0.00 | 100 | 50 | | 123 | Shanta | Vollman | SVOLLMAN | 650.123.4234 | 1987-07-10 | ST_MAN | 6500.00 | 0.00 | 100 | 50 | | 124 | Kevin | Mourgos | KMOURGOS | 650.123.5234 | 1987-07-11 | ST_MAN | 5800.00 | 0.00 | 100 | 50 | | 125 | Julia | Nayer | JNAYER | 650.124.1214 | 1987-07-12 | ST_CLERK | 3200.00 | 0.00 | 120 | 50 | | 126 | Irene | Mikkilineni | IMIKKILI | 650.124.1224 | 1987-07-13 | ST_CLERK | 2700.00 | 0.00 | 120 | 50 | | 127 | James | Landry | JLANDRY | 650.124.1334 | 1987-07-14 | ST_CLERK | 2400.00 | 0.00 | 120 | 50 | | 128 | Steven | Markle | SMARKLE | 650.124.1434 | 1987-07-15 | ST_CLERK | 2200.00 | 0.00 | 120 | 50 | | 129 | Laura | Bissot | LBISSOT | 650.124.5234 | 1987-07-16 | ST_CLERK | 3300.00 | 0.00 | 121 | 50 | | 130 | Mozhe | Atkinson | MATKINSO | 650.124.6234 | 1987-07-17 | ST_CLERK | 2800.00 | 0.00 | 121 | 50 | | 131 | James | Marlow | JAMRLOW | 650.124.7234 | 1987-07-18 | ST_CLERK | 2500.00 | 0.00 | 121 | 50 | | 132 | TJ | Olson | TJOLSON | 650.124.8234 | 1987-07-19 | ST_CLERK | 2100.00 | 0.00 | 121 | 50 | | 133 | Jason | Mallin | JMALLIN | 650.127.1934 | 1987-07-20 | ST_CLERK | 3300.00 | 0.00 | 122 | 50 | | 134 | Michael | Rogers | MROGERS | 650.127.1834 | 1987-07-21 | ST_CLERK | 2900.00 | 0.00 | 122 | 50 | | 135 | Ki | Gee | KGEE | 650.127.1734 | 1987-07-22 | ST_CLERK | 2400.00 | 0.00 | 122 | 50 | | 136 | Hazel | Philtanker | HPHILTAN | 650.127.1634 | 1987-07-23 | ST_CLERK | 2200.00 | 0.00 | 122 | 50 | | 137 | Renske | Ladwig | RLADWIG | 650.121.1234 | 1987-07-24 | ST_CLERK | 3600.00 | 0.00 | 123 | 50 | | 138 | Stephen | Stiles | SSTILES | 650.121.2034 | 1987-07-25 | ST_CLERK | 3200.00 | 0.00 | 123 | 50 | | 139 | John | Seo | JSEO | 650.121.2019 | 1987-07-26 | ST_CLERK | 2700.00 | 0.00 | 123 | 50 | | 140 | Joshua | Patel | JPATEL | 650.121.1834 | 1987-07-27 | ST_CLERK | 2500.00 | 0.00 | 123 | 50 | | 141 | Trenna | Rajs | TRAJS | 650.121.8009 | 1987-07-28 | ST_CLERK | 3500.00 | 0.00 | 124 | 50 | | 142 | Curtis | Davies | CDAVIES | 650.121.2994 | 1987-07-29 | ST_CLERK | 3100.00 | 0.00 | 124 | 50 | | 143 | Randall | Matos | RMATOS | 650.121.2874 | 1987-07-30 | ST_CLERK | 2600.00 | 0.00 | 124 | 50 | | 144 | Peter | Vargas | PVARGAS | 650.121.2004 | 1987-07-31 | ST_CLERK | 2500.00 | 0.00 | 124 | 50 | | 145 | John | Russell | JRUSSEL | 011.44.1344.429268 | 1987-08-01 | SA_MAN | 14000.00 | 0.40 | 100 | 80 | | 146 | Karen | Partners | KPARTNER | 011.44.1344.467268 | 1987-08-02 | SA_MAN | 13500.00 | 0.30 | 100 | 80 | | 147 | Alberto | Errazuriz | AERRAZUR | 011.44.1344.429278 | 1987-08-03 | SA_MAN | 12000.00 | 0.30 | 100 | 80 | | 148 | Gerald | Cambrault | GCAMBRAU | 011.44.1344.619268 | 1987-08-04 | SA_MAN | 11000.00 | 0.30 | 100 | 80 | | 149 | Eleni | Zlotkey | EZLOTKEY | 011.44.1344.429018 | 1987-08-05 | SA_MAN | 10500.00 | 0.20 | 100 | 80 | | 150 | Peter | Tucker | PTUCKER | 011.44.1344.129268 | 1987-08-06 | SA_REP | 10000.00 | 0.30 | 145 | 80 | | 151 | David | Bernstein | DBERNSTE | 011.44.1344.345268 | 1987-08-07 | SA_REP | 9500.00 | 0.25 | 145 | 80 | | 152 | Peter | Hall | PHALL | 011.44.1344.478968 | 1987-08-08 | SA_REP | 9000.00 | 0.25 | 145 | 80 | | 153 | Christopher | Olsen | COLSEN | 011.44.1344.498718 | 1987-08-09 | SA_REP | 8000.00 | 0.20 | 145 | 80 | | 154 | Nanette | Cambrault | NCAMBRAU | 011.44.1344.987668 | 1987-08-10 | SA_REP | 7500.00 | 0.20 | 145 | 80 | | 155 | Oliver | Tuvault | OTUVAULT | 011.44.1344.486508 | 1987-08-11 | SA_REP | 7000.00 | 0.15 | 145 | 80 | | 156 | Janette | King | JKING | 011.44.1345.429268 | 1987-08-12 | SA_REP | 10000.00 | 0.35 | 146 | 80 | | 157 | Patrick | Sully | PSULLY | 011.44.1345.929268 | 1987-08-13 | SA_REP | 9500.00 | 0.35 | 146 | 80 | | 158 | Allan | McEwen | AMCEWEN | 011.44.1345.829268 | 1987-08-14 | SA_REP | 9000.00 | 0.35 | 146 | 80 | | 159 | Lindsey | Smith | LSMITH | 011.44.1345.729268 | 1987-08-15 | SA_REP | 8000.00 | 0.30 | 146 | 80 | | 160 | Louise | Doran | LDORAN | 011.44.1345.629268 | 1987-08-16 | SA_REP | 7500.00 | 0.30 | 146 | 80 | | 161 | Sarath | Sewall | SSEWALL | 011.44.1345.529268 | 1987-08-17 | SA_REP | 7000.00 | 0.25 | 146 | 80 | | 162 | Clara | Vishney | CVISHNEY | 011.44.1346.129268 | 1987-08-18 | SA_REP | 10500.00 | 0.25 | 147 | 80 | | 163 | Danielle | Greene | DGREENE | 011.44.1346.229268 | 1987-08-19 | SA_REP | 9500.00 | 0.15 | 147 | 80 | | 164 | Mattea | Marvins | MMARVINS | 011.44.1346.329268 | 1987-08-20 | SA_REP | 7200.00 | 0.10 | 147 | 80 | | 165 | David | Lee | DLEE | 011.44.1346.529268 | 1987-08-21 | SA_REP | 6800.00 | 0.10 | 147 | 80 | | 166 | Sundar | Ande | SANDE | 011.44.1346.629268 | 1987-08-22 | SA_REP | 6400.00 | 0.10 | 147 | 80 | | 167 | Amit | Banda | ABANDA | 011.44.1346.729268 | 1987-08-23 | SA_REP | 6200.00 | 0.10 | 147 | 80 | | 168 | Lisa | Ozer | LOZER | 011.44.1343.929268 | 1987-08-24 | SA_REP | 11500.00 | 0.25 | 148 | 80 | | 169 | Harrison | Bloom | HBLOOM | 011.44.1343.829268 | 1987-08-25 | SA_REP | 10000.00 | 0.20 | 148 | 80 | | 170 | Tayler | Fox | TFOX | 011.44.1343.729268 | 1987-08-26 | SA_REP | 9600.00 | 0.20 | 148 | 80 | | 171 | William | Smith | WSMITH | 011.44.1343.629268 | 1987-08-27 | SA_REP | 7400.00 | 0.15 | 148 | 80 | | 172 | Elizabeth | Bates | EBATES | 011.44.1343.529268 | 1987-08-28 | SA_REP | 7300.00 | 0.15 | 148 | 80 | | 173 | Sundita | Kumar | SKUMAR | 011.44.1343.329268 | 1987-08-29 | SA_REP | 6100.00 | 0.10 | 148 | 80 | | 174 | Ellen | Abel | EABEL | 011.44.1644.429267 | 1987-08-30 | SA_REP | 11000.00 | 0.30 | 149 | 80 | | 175 | Alyssa | Hutton | AHUTTON | 011.44.1644.429266 | 1987-08-31 | SA_REP | 8800.00 | 0.25 | 149 | 80 | | 176 | Jonathon | Taylor | JTAYLOR | 011.44.1644.429265 | 1987-09-01 | SA_REP | 8600.00 | 0.20 | 149 | 80 | | 177 | Jack | Livingston | JLIVINGS | 011.44.1644.429264 | 1987-09-02 | SA_REP | 8400.00 | 0.20 | 149 | 80 | | 178 | Kimberely | Grant | KGRANT | 011.44.1644.429263 | 1987-09-03 | SA_REP | 7000.00 | 0.15 | 149 | 0 | | 179 | Charles | Johnson | CJOHNSON | 011.44.1644.429262 | 1987-09-04 | SA_REP | 6200.00 | 0.10 | 149 | 80 | | 180 | Winston | Taylor | WTAYLOR | 650.507.9876 | 1987-09-05 | SH_CLERK | 3200.00 | 0.00 | 120 | 50 | | 181 | Jean | Fleaur | JFLEAUR | 650.507.9877 | 1987-09-06 | SH_CLERK | 3100.00 | 0.00 | 120 | 50 | | 182 | Martha | Sullivan | MSULLIVA | 650.507.9878 | 1987-09-07 | SH_CLERK | 2500.00 | 0.00 | 120 | 50 | | 183 | Girard | Geoni | GGEONI | 650.507.9879 | 1987-09-08 | SH_CLERK | 2800.00 | 0.00 | 120 | 50 | | 184 | Nandita | Sarchand | NSARCHAN | 650.509.1876 | 1987-09-09 | SH_CLERK | 4200.00 | 0.00 | 121 | 50 | | 185 | Alexis | Bull | ABULL | 650.509.2876 | 1987-09-10 | SH_CLERK | 4100.00 | 0.00 | 121 | 50 | | 186 | Julia | Dellinger | JDELLING | 650.509.3876 | 1987-09-11 | SH_CLERK | 3400.00 | 0.00 | 121 | 50 | | 187 | Anthony | Cabrio | ACABRIO | 650.509.4876 | 1987-09-12 | SH_CLERK | 3000.00 | 0.00 | 121 | 50 | | 188 | Kelly | Chung | KCHUNG | 650.505.1876 | 1987-09-13 | SH_CLERK | 3800.00 | 0.00 | 122 | 50 | | 189 | Jennifer | Dilly | JDILLY | 650.505.2876 | 1987-09-14 | SH_CLERK | 3600.00 | 0.00 | 122 | 50 | | 190 | Timothy | Gates | TGATES | 650.505.3876 | 1987-09-15 | SH_CLERK | 2900.00 | 0.00 | 122 | 50 | | 191 | Randall | Perkins | RPERKINS | 650.505.4876 | 1987-09-16 | SH_CLERK | 2500.00 | 0.00 | 122 | 50 | | 192 | Sarah | Bell | SBELL | 650.501.1876 | 1987-09-17 | SH_CLERK | 4000.00 | 0.00 | 123 | 50 | | 193 | Britney | Everett | BEVERETT | 650.501.2876 | 1987-09-18 | SH_CLERK | 3900.00 | 0.00 | 123 | 50 | | 194 | Samuel | McCain | SMCCAIN | 650.501.3876 | 1987-09-19 | SH_CLERK | 3200.00 | 0.00 | 123 | 50 | | 195 | Vance | Jones | VJONES | 650.501.4876 | 1987-09-20 | SH_CLERK | 2800.00 | 0.00 | 123 | 50 | | 196 | Alana | Walsh | AWALSH | 650.507.9811 | 1987-09-21 | SH_CLERK | 3100.00 | 0.00 | 124 | 50 | | 197 | Kevin | Feeney | KFEENEY | 650.507.9822 | 1987-09-22 | SH_CLERK | 3000.00 | 0.00 | 124 | 50 | | 198 | Donald | OConnell | DOCONNEL | 650.507.9833 | 1987-09-23 | SH_CLERK | 2600.00 | 0.00 | 124 | 50 | | 199 | Douglas | Grant | DGRANT | 650.507.9844 | 1987-09-24 | SH_CLERK | 2600.00 | 0.00 | 124 | 50 | | 200 | Jennifer | Whalen | JWHALEN | 515.123.4444 | 1987-09-25 | AD_ASST | 4400.00 | 0.00 | 101 | 10 | | 201 | Michael | Hartstein | MHARTSTE | 515.123.5555 | 1987-09-26 | MK_MAN | 13000.00 | 0.00 | 100 | 20 | | 202 | Pat | Fay | PFAY | 603.123.6666 | 1987-09-27 | MK_REP | 6000.00 | 0.00 | 201 | 20 | | 203 | Susan | Mavris | SMAVRIS | 515.123.7777 | 1987-09-28 | HR_REP | 6500.00 | 0.00 | 101 | 40 | | 204 | Hermann | Baer | HBAER | 515.123.8888 | 1987-09-29 | PR_REP | 10000.00 | 0.00 | 101 | 70 | | 205 | Shelley | Higgins | SHIGGINS | 515.123.8080 | 1987-09-30 | AC_MGR | 12000.00 | 0.00 | 101 | 110 | | 206 | William | Gietz | WGIETZ | 515.123.8181 | 1987-10-01 | AC_ACCOUNT | 8300.00 | 0.00 | 205 | 110 | +-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+
Sample table: departments
+---------------+----------------------+------------+-------------+ | DEPARTMENT_ID | DEPARTMENT_NAME | MANAGER_ID | LOCATION_ID | +---------------+----------------------+------------+-------------+ | 10 | Administration | 200 | 1700 | | 20 | Marketing | 201 | 1800 | | 30 | Purchasing | 114 | 1700 | | 40 | Human Resources | 203 | 2400 | | 50 | Shipping | 121 | 1500 | | 60 | IT | 103 | 1400 | | 70 | Public Relations | 204 | 2700 | | 80 | Sales | 145 | 2500 | | 90 | Executive | 100 | 1700 | | 100 | Finance | 108 | 1700 | | 110 | Accounting | 205 | 1700 | | 120 | Treasury | 0 | 1700 | | 130 | Corporate Tax | 0 | 1700 | | 140 | Control And Credit | 0 | 1700 | | 150 | Shareholder Services | 0 | 1700 | | 160 | Benefits | 0 | 1700 | | 170 | Manufacturing | 0 | 1700 | | 180 | Construction | 0 | 1700 | | 190 | Contracting | 0 | 1700 | | 200 | Operations | 0 | 1700 | | 210 | IT Support | 0 | 1700 | | 220 | NOC | 0 | 1700 | | 230 | IT Helpdesk | 0 | 1700 | | 240 | Government Sales | 0 | 1700 | | 250 | Retail Sales | 0 | 1700 | | 260 | Recruiting | 0 | 1700 | | 270 | Payroll | 0 | 1700 | +---------------+----------------------+------------+-------------+
SQLite Code:
-- Selecting specific columns with aliases for clarity
SELECT depart_name AS 'Department Name',
COUNT(*) AS 'No of Employees'
-- Specifying the primary table from which to retrieve the data, in this case, "departments"
FROM departments
-- Performing an inner join with the "employees" table based on the common column "department_id"
INNER JOIN employees
ON employees.department_id = departments.department_id
-- Grouping the results by department_id and depart_name to count employees per department
GROUP BY departments.department_id, depart_name
-- Sorting the results in ascending order based on depart_name
ORDER BY depart_name;
Output:
Department Name No of Employees --------------- --------------- Accounting 2 Administration 1 Executive 3 Finance 6 Human Resources 1 IT 5 Marketing 2 Public Relation 1 Purchasing 6 Sales 34 Shipping 45
Explanation:
The above SQLite query retrieves information about departments, including the department name and the count of employees in each department. The results are grouped by department and sorted in ascending order based on the department name.
Here's a brief explanation of each part of SQLite code:
- SELECT clause:
- It selects specific columns with aliases for clarity. The columns include depart_name from the "departments" table (aliased as "Department Name") and the count of employees (COUNT(*)) with the alias 'No of Employees.'
- FROM clause:
- Specifies the primary table from which to retrieve the data, in this case, the "departments" table.
- INNER JOIN clause:
- Perform an inner join with the "employees" table based on the common column "department_id."
- ON clause:
- Specifies the join condition using the ON keyword. The condition is (employees.department_id = departments.department_id), indicating that the "departments" and "employees" tables are joined based on the common column "department_id."
- GROUP BY clause:
- Group the results by the columns departments.department_id and depart_name. This allows counting the number of employees per department.
- ORDER BY clause:
- Sorts the results in ascending order based on the column depart_name.
Practice SQLite Online
Model Database
Structure of 'hr' database :
Improve this sample solution and post your code through Disqus.
Previous: Write a query to find the names (first_name, last_name) and hire date of the employees who were hired after 'Jones'.
Next: Write a query to find the employee ID, job title number of days between ending date and starting date for all jobs in department 90 from job history.
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