Syntax basics
Syntax basics
One of the most frequently used SQL statements is the SELECT statement, which extracts specified columns from one or more database tables to build a recordset. Here’s the basic syntax for a SELECT statement:
SELECTColumnNameFROMTableName
You can add line breaks, tabs, and other white space to your statements to clarify the logic: SQL ignores all white space. The following example shows a valid statement:
SELECT PaidDues FROM Members
The following keywords identify commonly used SQL commands:
Keyword |
Description |
|---|---|
SELECT |
Retrieves the specified records from a database |
INSERT |
Adds a new record in a database table |
UPDATE |
Changes values in specified database records |
DELETE |
Removes specified database records |
The following keywords are used to refine SQL statements:
Keyword |
Description |
|---|---|
FROM |
Names the data source for an operation |
WHERE |
Sets one or more conditions for the operation |
ORDER BY |
Sorts the recordset rows in a specified order |
GROUP BY |
Groups the recordset by the specified select list items |
The following operators specify conditions and perform logical and numeric functions:
Operator |
Meaning |
|---|---|
|
Equal to |
|
Like (wildcards OK) |
|
Not equal to |
|
Not like (wildcards OK) |
|
Less than |
|
Greater than |
|
Less than or equal to |
|
Greater than or equal to |
AND |
Both conditions must be met, such as Louisiana AND Texas |
OR |
At least one condition must be met, such as Smith OR Smyth |
NOT |
Exclude the condition following, such as Paris NOT France |
If the item being compared is text, place it in single quotes as in the following example:
...WHERE Country = 'Germany'
If the item being compared is a date and you’re working with a Microsoft Access database, enclose it with # signs:
...WHERE DateOfBirth < #01/01/1970#
Other databases may have their own date conventions. Consult the database system’s documentation.
Some database systems may use non-standard SQL syntax in their products. Check your database system’s documentation.
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