SELECT Reference
From SQLZoo
The SELECT command is used to show data from a database.
The output from a SELECT statement is always a grid - with a number of rows and a number of columns.
Simple SELECT
The simplest SELECT commands involve a single table:
SQL | Result | ||||||
---|---|---|---|---|---|---|---|
SELECT name, population
FROM bbc
WHERE region='North America' |
|
- The SELECT line determines which columns to show - in this case
name
andpopulation
, both of which are columns of the bbc table. - The WHERE clause determines which rows to show
- The SELECT statement may involve data from more than one table using a JOIN or a UNION.
- SELECT statements may nested - that is the output from one SELECT may be the input to another SELECT.
- The output from a SELECT may be added to another table using INSERT .. SELECT
- The select statement may aggregate values using a SELECT .. GROUP BY clause