SELECT statement falls under DQL (Data Query Language ) of SQL. It is used to query or retrieve data from sql. Here is a sample table for use to practise. The table name is trees.
+—————————————–Table————————————–+
| PlotID | TreeTagNumber | SpeciesID | DBH | Height | Researcher | Date |
|---|---|---|---|---|---|---|
| 110 | 461 | 5 | 3.00 | 4.00 | Fernando | 1999-01-01 |
| 110 | 462 | 51 | 19.30 | 25.73 | Fernando | 1999-01-01 |
| 110 | 465 | 76 | 4.10 | 5.46 | Fernando | 1999-01-01 |
| 110 | 466 | 76 | 4.50 | 6.00 | Fernando | 1999-01-01 |
| 110 | 467 | 76 | 4.40 | 5.86 | Fernando | 1999-01-01 |
| 110 | 468 | 76 | 9.50 | 12.66 | Fernando | 1999-01-01 |
| 110 | 469 | 76 | 5.30 | 7.06 | Fernando | 1999-01-01 |
| 110 | 470 | 62 | 7.20 | 9.60 | Fernando | 1999-01-01 |
| 110 | 471 | 62 | 3.40 | 4.53 | Fernando | 1999-01-01 |
| 110 | 472 | 62 | 7.10 | 9.46 | Fernando | 1999-01-01 |
+——————————————-+——————————————+
SELECT * from trees;
GENERIC SYNTAX below
SELECT * from TABLENAME
This is show all the columns and rows in table trees. If you want to see only specific columns you have to issue the sql command like this
[GENERIC FORMAT]
SELECT column1,column2 from TABLENAME
column1 & column2 are column names in the table.
SELECT PlotID,TreeTagNumber from trees;
This command displays only PlotID and TreeTagNumber from above table. The output will be like this
+————————————OUTPUT——————————————+
| PlotID | TreeTagNumber |
|---|---|
| 110 | 461 |
| 110 | 462 |
| 110 | 465 |
| 110 | 466 |
| 110 | 467 |
| 110 | 468 |
| 110 | 469 |
| 110 | 470 |
| 110 | 471 |
| 110 | 472 |
+——————————————-+——————————————+