SELECT statement purpose is to retrieve information from one or more tables. This SQL statement you'll probably use most frequently.
SELECT to retrieve table data you must, at a minimum, specify two pieces of information what you want to select, and from where you want to select it.
Fetch single column data using
We'll start with a simple SQL
SELECT statement. The following statement uses the
SELECT statement to retrieve a single column called
prod_name from the
products table. The desired column name is specified right after the
SELECT keyword, and the
FROM keyword specifies the name of the table from which to retrieve the data.
SELECT prod_name FROM products;
The output from this statement is shown in the following:
+------------+ | prod_name | +------------+ | product 1 | | product 2 | | product 3 | | product 4 | | product 5 | | product 6 | | product 7 | | product 8 | | product 9 | | product 10 | | product 11 | +------------+
SELECT statement like the one just shown above returns all the rows in a table. The returned data is not filtered and sorted.
All extra white space within a SQL statement is ignored when that statement is processed. SQL statements can be specified on one long line or broken up over many lines. Most SQL developers find that breaking up statements over multiple lines makes them easier to read and debug.
SQL Statements Case Sensitivity
It is important to note that SQL statements are not case sensitive, so
SELECT is the same as
select, which is the same as
Select. Many SQL developers find that using uppercase for all SQL keywords and lowercase for column and table names makes code easier to read and debug.
Be aware that while the SQL language is not case sensitive. In MySQL 4.1 and earlier, identifiers (the names of databases, tables, and columns) were case sensitive by default, and as of MySQL 4.1.1, identifiers are not case sensitive by default.
Multiple SQL statements must be separated by semicolons. However, MySQL does not require that a semicolon be specified after single statements. If you are using the
mysql command-line client, the semicolon is always needed.