The substring is a string beginning at 8, which is SQL. In the second statement, we extract a substring started at position 8 and we omit the length parameter.

In the first statement, we extract a substring that has length of 8 and it is started at the first character of the PostgreSQL string. See the following examples: SELECT SUBSTRING ( 'PostgreSQL', 1, 8) - PostgreS SELECT SUBSTRING ( 'PostgreSQL', 8) - SQL Code language: SQL (Structured Query Language) ( sql ) If you omit the length parameter, the substring function returns the whole string started at start_position. If the sum of start_position and length is greater than the number of characters in the string, the substring function returns the whole string beginning at start_position. length is a positive integer that determines the number of characters that you want to extract from the string beginning at start_position.Though in other database systems such as MySQL the substring function can accept a negative start_position. If start_position equals zero, the substring starts at the first character of the string. start_position is an integer that specifies where you want to extract the substring.string is a string whose data type is char, varchar, text, etc.The following illustrates the syntax of the substring function: SUBSTRING ( string ,start_position, length ) Code language: SQL (Structured Query Language) ( sql ) The substring function returns a part of string. Introduction to PostgreSQL substring function Summary: in this tutorial, we will introduce you to PostgreSQL substring function that extracts a substring from a string.

Php substring everything after a string