Added String Length article

Author: waqasm78

docs2/pages/documentations/string/string-length.md

@@ -0,0 +1,41 @@
+# String_Length
+
+`String_Length` returns the number of characters in the `source` string.
+
+```csharp
+String_Length (
+	@source NVARCHAR (MAX), 
+	)
+RETURNS INT
+```
+
+## Parameters
+
+  - **source**: The source string.
+
+## Returns
+
+The number of characters in the `source` string.
+
+## Example
+
+```csharp
+SELECT SQLNET::String_Length('This is a string.')
+```
+
+# String_Length4k
+
+It is equivalent to `String_Length` except no NVARCHAR(MAX) parameters; it can be used when input data will never be over 4000 characters as this function offers better performance.
+
+```csharp
+String_Length4k (
+	@source NVARCHAR (4000), 
+	)
+RETURNS INT
+```
+
+## Example
+
+```csharp
+SELECT SQLNET::String_Length4k('This is a string.')
+```

docs2/pages/documentations/string/string.md

@@ -30,3 +30,4 @@ Represents text as a sequence of UTF-16 code units.
 | [String_LastIndexOfInvariantCultureIgnoreCase(source, searchValue)](/string-last-indexof-invariant-culture-ignore-case) | Returns the zero-based index of the last occurrence of the specified string using culture-sensitive sort rules, the invariant culture, and ignoring the case of the strings. | [Try it]()|
 | [String_LastIndexOfOrdinal(source, searchValue)](/string-last-indexof-ordinal) | Returns the zero-based index of the last occurrence of the specified string using ordinal (binary) sort rules. | [Try it]()|
 | [String_LastIndexOfOrdinalIgnoreCase(source, searchValue)](/string-last-indexof-ordinal-ignore-case) | Returns the zero-based index of the last occurrence of the specified string using ordinal (binary) sort rules, and ignoring the case of the strings. | [Try it]()|
+| [String_Leangth(source)](/string-length) | Returns the number of characters in the specified string. | [Try it]()|