SQLite Exercise: Get 3 minimum salaries
Write a query to get 3 minimum salaries.
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 | +-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+
SQLite Code:
-- Selecting distinct salary values from the "employees" table, aliasing it as "a"
SELECT DISTINCT salary
-- Alias for the "employees" table as "a"
FROM employees a
-- Filtering the results to include only rows where the count of distinct salaries is less than or equal to 3
WHERE 3 >=
-- Subquery to count the distinct salary values for each row in the "employees" table, aliasing it as "b"
(SELECT COUNT(DISTINCT salary)
-- Alias for the "employees" table as "b"
FROM employees b
-- Further filtering the subquery to include only rows where the salary in "a" is greater than or equal to the salary in "b"
WHERE a.salary >= b.salary)
-- Ordering the results by salary in descending order
ORDER BY a.salary DESC;
Output:
salary ---------- 2400 2200 2100
Explanation:
The above SQLite query selects distinct salary values from the "employees" table (aliased as "a") and filters the results to include only those rows where the count of distinct salaries is less than or equal to 3. The subquery is used to compare each salary in "a" with all other salaries in "b" and count how many unique salary values are greater than or equal to the salary in "a." The final result is then ordered by salary in descending order.
Here's a brief explanation of each part of SQLite code:
- SELECT clause:
- It selects distinct salary values from the "employees" table, and these results are aliased as "a."
- FROM clause:
- Specifies the table from which to retrieve the data, in this case, the "employees" table. The table is given an alias "a."
- WHERE clause:
- Filters the results to include only those rows where the count of distinct salaries is less than or equal to 3.
- Subquery:
- The subquery (SELECT COUNT(DISTINCT salary) FROM employees b WHERE a.salary >= b.salary) counts the distinct salary values for each row in the "employees" table. It ensures that only rows where the salary in "a" is greater than or equal to the salary in "b" are considered.
- ORDER BY clause:
- Orders the results by salary in descending order (ORDER BY a.salary DESC).
Practice SQLite Online
Model Database
Structure of 'hr' database :
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