ODBC and JDBC Developer’s Guide

26 FileMaker ODBC and JDBC Developer’s Guide
The SELECT statement can use a variety of clauses:
SELECT [DISTINCT] {* | column_expression [[AS] column_alias],...}
FROM table_name [table_alias], ...
[ WHERE expr1 rel_operator expr2 ]
[ GROUP BY {column_expression, ...} ]
[ HAVING expr1 rel_operator expr2 ]
[ UNION [ALL] (SELECT...) ]
[ ORDER BY {sort_expression [DESC | ASC]}, ... ]
[ FOR UPDATE [OF {column_expression, ...}] ]
Items in brackets are optional.
Note SELECT * on larger databases and SELECT statements that use table aliases or literals in the
projection list might not function correctly. To avoid potential confusion, avoid wildcards and specify table
and column names without aliases.
column_alias can be used to give the column a more descriptive name, or to abbreviate a longer column
name. For example, to assign the alias
department to the column dept:
SELECT dept AS department FROM emp
Field names can be prefixed with the table name or the table alias. For example, EMP.LAST_NAME or
E.LAST_NAME, where E is the alias for the table EMP.
The DISTINCT operator can precede the first column expression. This operator eliminates duplicate rows
from the result of a query. For example:
SELECT DISTINCT dept FROM emp
Note If you attempt to retrieve data from a table with no columns, the SELECT statement fails.
Examples
The following example retrieves the names of employees who make at least 20,000:
SELECT last_name,first_name FROM emp WHERE salary >= 20000
Use this SQL clause To
FROM Indicate which tables are used in the SELECT statement.
WHERE Specify the conditions that records must meet to be retrieved (like a FileMaker Pro find
request).
GROUP BY Specify the names of one or more fields by which the returned values should be grouped.
This clause is used to return a set of aggregate values by returning one row for each group
(like a FileMaker Pro subsummary).
HAVING Specify conditions for groups of records (for example, display only the departments that
have salaries totaling more than $200,000). This clause is only valid if you have already
defined a GROUP BY clause.
UNION Combine the results of two or more SELECT statements into a single result.
ORDER BY Indicate how the records are sorted
FOR UPDATE Lock the records of the database table selected by the SELECT statement