SELECT BIT_LENGTH ( 'A') - 8 bits Code language: SQL (Structured Query Language) ( sql ) SELECT BIT_LENGTH ( '€') - 24 bits Code language: SQL (Structured Query Language) ( sql ) See the following examples of using the bit_length function. To measure the number of bits of a string, you use the bit_length function as follows: BIT_LENGTH(string) Code language: SQL (Structured Query Language) ( sql ) SELECT LENGTH ( '€') - 1 Code language: SQL (Structured Query Language) ( sql ) However, with the length function, it returns just 1. SELECT OCTET_LENGTH ( '€') - 3 bytes Code language: SQL (Structured Query Language) ( sql ) See the following example: SELECT OCTET_LENGTH ( 'A') - 1 byte Code language: SQL (Structured Query Language) ( sql ) To get the number of bytes in a string, you use the octet_length function as follows: OCTET_LENGTH(string) Code language: SQL (Structured Query Language) ( sql ) LENGTH AS domain_name Code language: SQL (Structured Query Language) ( sql )īesides the length function, PostgreSQL provides the char_length and character_length functions that provide the same functionality. The following statement gets the user name and domain from the an email address using substring, strpos, and lengthfunctions. We often use the length function with other string functions such as replace, substring, etc., to manipulate string more efficiently. In this case, you use type cast to convert the number into a string and use the length function as the following example: SELECT LENGTH ( CAST( 12345 AS TEXT)) - 5 Code language: SQL (Structured Query Language) ( sql ) Sometimes, you may want to measure the length of a number instead of a string. ORDER BY len Code language: SQL (Structured Query Language) ( sql ) LENGTH (first_name || ' ' || last_name) len FROM The following query gets the full names of customers in the customer table and uses the length function to get the number of characters in their names. SELECT LENGTH ( NULL) - NULL Code language: SQL (Structured Query Language) ( sql ) If you pass a NULL value to the length function, it returns a NULL value. However, a string that holds a space character: SELECT LENGTH ( ' ') - 1 Code language: SQL (Structured Query Language) ( sql ) SELECT LENGTH ( '') - 0 Code language: SQL (Structured Query Language) ( sql ) Notice that a string can hold an empty string, which is not a null value. See the following example of using the length function: SELECT LENGTH ( 'PostgreSQL Tutorial') - 19 Code language: SQL (Structured Query Language) ( sql ) The length function returns the number of characters in the string. A string can be any of the following data types: The length function accepts a string as a parameter. The following illustrates the syntax of the length function: LENGTH(string) Code language: SQL (Structured Query Language) ( sql ) Summary: in this tutorial, we will show you various PostgreSQL length functions that return the number of characters or the number of bytes of a string.
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