1
, 2
1. General Form of a SQL SELECT Statement
SELECT TOP <n> <field(s)>
FROM <tableName(s)>
WHERE <condition(s)>
GROUP BY <expression>
HAVING <condition>
ORDER BY <expression>
SELECT Extracts data from the table (Fields that need to be displayed)
TOP <n> Limits the number of rows displayed in a table
FROM Found in the specified table(s)
WHERE ● Will select all records where the field(s) condition(s) are met
<condition> ● Condition can consist of any Boolean condition, using any number of fields
● A field value can be compared to a value, but not to an aggregate
The condition always consists of:
● A field name, followed by a relational operator, then a comparison value
GROUP BY Provides the result of a (function) for each (category) of rows
<expression> Used to assign values to a specific field - keyword ‘each’
HAVING Removes rows from a GROUP BY Result Set
<condition> (Same way as a WHERE clause, but is used for aggregate functions → COUNT( ),
SUM( ) etc.)
ORDER BY Ranks selected fields only, in order of the fields entered (field1 before field2)
<expression>
Whenever there is a primary / foreign key in one table that links to a foreign key (a primary key in
another table) a relationship exists between the two tables and we can perform queries that make use
of that relationship to combine data from both tables
The primary / foreign key relationships that exist in this database are:
● ActNum primary key in tblActs links to the foreign key ActNum in tblEntrants
- the relationship is one-to-many, where one act may have many entrants
● ActNum primary key in tblActs links to the foreign key ActNum in tblPoints
- the relationship is one-to-one, meaning that one act has one set of points
When there is a one-to-one relationship between primary keys of two tables, the primary key of each
table is considered to be a foreign key in the other table
2
, 2
1. General Form of a SQL SELECT Statement
SELECT TOP <n> <field(s)>
FROM <tableName(s)>
WHERE <condition(s)>
GROUP BY <expression>
HAVING <condition>
ORDER BY <expression>
SELECT Extracts data from the table (Fields that need to be displayed)
TOP <n> Limits the number of rows displayed in a table
FROM Found in the specified table(s)
WHERE ● Will select all records where the field(s) condition(s) are met
<condition> ● Condition can consist of any Boolean condition, using any number of fields
● A field value can be compared to a value, but not to an aggregate
The condition always consists of:
● A field name, followed by a relational operator, then a comparison value
GROUP BY Provides the result of a (function) for each (category) of rows
<expression> Used to assign values to a specific field - keyword ‘each’
HAVING Removes rows from a GROUP BY Result Set
<condition> (Same way as a WHERE clause, but is used for aggregate functions → COUNT( ),
SUM( ) etc.)
ORDER BY Ranks selected fields only, in order of the fields entered (field1 before field2)
<expression>
Whenever there is a primary / foreign key in one table that links to a foreign key (a primary key in
another table) a relationship exists between the two tables and we can perform queries that make use
of that relationship to combine data from both tables
The primary / foreign key relationships that exist in this database are:
● ActNum primary key in tblActs links to the foreign key ActNum in tblEntrants
- the relationship is one-to-many, where one act may have many entrants
● ActNum primary key in tblActs links to the foreign key ActNum in tblPoints
- the relationship is one-to-one, meaning that one act has one set of points
When there is a one-to-one relationship between primary keys of two tables, the primary key of each
table is considered to be a foreign key in the other table
2
