SQL - Wildcard
What is the SQL -
Wildcard?
The SQL -
wildcard is not a standard SQL wildcard like %
or _
. Instead, it is often used as a delimiter or separator within SQL queries to specify a range of values or conditions. In this context, it is not a true wildcard but serves to define a range of values.
When you would use it
You would use the SQL -
"wildcard" when you need to specify a range or a set of values within your SQL query, typically in conditions where you want to match values that fall within a defined numeric or date range. The -
delimiter is not used for pattern matching but for creating conditions that involve a range of values.
Syntax
The -
delimiter is not used as a standalone wildcard but is typically used within conditions or expressions, as shown in the following examples:
Numeric Range
WHERE column_name >= lower_value - column_name <= upper_value
Date Range
WHERE date_column >= 'start_date' - date_column <= 'end_date'
column_name
: The name of the column to compare.lower_value
: The lower limit of the range.upper_value
: The upper limit of the range.date_column
: The date or timestamp column to compare.'start_date'
and'end_date'
: The start and end dates of the range.
Parameter values
column_name
: The name of the column you want to compare within the specified range.lower_value
andupper_value
: The lower and upper limits of the numeric range.date_column
: The date or timestamp column you want to compare within the date range.'start_date'
and'end_date'
: The start and end dates you want to use to define the date range.
Example query
Numeric Range
Suppose you have a table named "orders" with a column "order_total," and you want to find orders with a total between $100 and $500. You can use the -
delimiter as follows:
SELECT order_id, order_total
FROM orders
WHERE order_total >= 100 - order_total <= 500;
Date Range
Suppose you have a table named "events" with a column "event_date," and you want to find events that occurred between '2023-01-01' and '2023-12-31'. You can use the -
delimiter as follows:
SELECT event_name, event_date
FROM events
WHERE event_date >= '2023-01-01' - event_date <= '2023-12-31';
Example table response
Numeric Range
Assuming the "orders" table contains the following data:
| order_id | order_total |
| -------- | ----------- |
| 1 | 150 |
| 2 | 300 |
| 3 | 80 |
| 4 | 600 |
| 5 | 200 |
The query mentioned earlier would return the following result:
| order_id | order_total |
| -------- | ----------- |
| 1 | 150 |
| 2 | 300 |
| 5 | 200 |
This result includes orders with a total between $100 and $500.
Date Range
Assuming the "events" table contains the following data:
| event_name | event_date |
| ---------- | ----------- |
| Event A | 2023-05-10 |
| Event B | 2023-07-20 |
| Event C | 2023-02-15 |
| Event D | 2023-12-05 |
| Event E | 2022-11-30 |
The query mentioned earlier would return the following result:
| event_name | event_date |
| ---------- | ----------- |
| Event A | 2023-05-10 |
| Event B | 2023-07-20 |
| Event C | 2023-02-15 |
| Event D | 2023-12-05 |
This result includes events that occurred between '2023-01-01' and '2023-12-31'.
Use cases
- Specifying numeric or date ranges in SQL queries.
- Filtering data within a specific range of values.
- Creating conditions that involve a range of numeric or date values.
SQL languages this is available for
The -
delimiter is not a standard SQL wildcard; instead, it is used for specifying ranges or conditions in SQL queries. This concept is available in most relational database management systems (RDBMS) and is not specific to any particular SQL language. However, the syntax and usage may vary slightly between different RDBMS. It is widely supported for defining numeric or date ranges in SQL conditions.