1. The population of 'France'. Strings should be in 'single quotes';
Results
2. The names and population densities for the very large
countries. We can use mathematical and string expressions as well as
field names and constants.
Results
3. Where to find some very small, very rich countries. We use AND to ensure that two or more conditions hold
true.
Results
4. Which of Ceylon, Iran,
Persia and Sri Lanka is the
name of a country? The word IN allows us to check if an item is in a list.
Results
5. What are the countries beginning with D? The word LIKE permits pattern matching - % is the
wildcard.
Results
6. Which countries are not too small and not too big? BETWEEN allows range checking - note that it is
inclusive.
Results
Simple use of
SELECT
and
WHERE
These statements take the form :
SELECT attribute-list
FROM table-name
WHERE condition
attribute-list
This is usually a comma separated list of attributes
(field names)
Expressions involving these attributes may be used. The
normal mathematical operators +, -, *, / may be used on
numeric values. String values may be concatenated using
||
To select all attributes use *
The attributes in this case are: name, region, area,
population and gdp
table-name
In these examples the table is always bbc.
condition
This is a boolean expression which each row must
satisfy.
Operators which may be used include AND,
OR, NOT, >,
>=, =, <, <=
The LIKE operator permits strings to be compared using
'wild cards'. The symbols _ and % are used to represent a
single character or a sequence of characters. Note that MS
Access SQL uses ? and * instead of _ and % .
The IN operator allows an item to be tested against a
list of values.