# How the GLENGTH() function works in Mariadb?

The MariaDB `GLENGTH()`

function is used to return the length of a lstring in units of its spatial reference.

The MariaDB `GLENGTH()`

function is used to return the length of a lstring in units of its spatial reference. It is commonly utilized in geographic information systems (GIS) to measure the distance between two points.

## Syntax

The syntax for the MariaDB `GLENGTH()`

function is as follows:

```
GLENGTH(lstring)
```

The function takes a `lstring`

as an argument and returns a numeric value representing its length.

## Examples

### Example 1: Basic Usage of `GLENGTH()`

This example demonstrates the basic usage of the `GLENGTH()`

function to calculate the length of a line.

```
SELECT GLENGTH(lstring(Point(0,0), Point(3,4)));
```

```
+---------------------------------------------+
| GLENGTH(lstring(Point(0,0), Point(3,4))) |
+---------------------------------------------+
| 5 |
+---------------------------------------------+
```

The output is `5`

, which is the length of the line segment connecting the points (0,0) and (3,4).

### Example 2: Using `GLENGTH()`

with Variables

This example shows how to use `GLENGTH()`

with variables representing points.

```
SET @Start = Point(0,0);
SET @End = Point(5,12);
SELECT GLENGTH(lstring(@Start, @End));
```

```
+-----------------------------------+
| GLENGTH(lstring(@Start, @End)) |
+-----------------------------------+
| 13 |
+-----------------------------------+
```

The output is `13`

, indicating the length of the line segment defined by the variables `@Start`

and `@End`

.

### Example 3: `GLENGTH()`

with a Defined lstring

Here, we define a `lstring`

and then use `GLENGTH()`

to find its length.

```
SET @Line = lstring(Point(0,0), Point(6,8));
SELECT GLENGTH(@Line);
```

```
+----------------+
| GLENGTH(@Line) |
+----------------+
| 10 |
+----------------+
```

The output `10`

is the length of the line segment stored in the variable `@Line`

.

### Example 4: `GLENGTH()`

with Invalid Input

This example shows what happens when `GLENGTH()`

is used with invalid input.

```
SELECT GLENGTH(Point(0,0));
```

```
+---------------------+
| GLENGTH(Point(0,0)) |
+---------------------+
| 0 |
+---------------------+
```

The output is `0`

because `GLENGTH()`

expects a `lstring`

, not a `Point`

.

## Related Functions

Below are a few functions related to the MariaDB `GLENGTH()`

function:

- MariaDB
`ST_Length()`

function is used to return the length of a`lstring`

in its spatial reference. - MariaDB
`ST_Distance()`

function is used to return the shortest distance between two geometries.

## Conclusion

Understanding the `GLENGTH()`

function in MariaDB is essential for working with spatial data, especially when calculating distances between points. By following the syntax and examples provided, users can effectively implement this function in their GIS applications.