How PostgreSQL’s CHARACTER_LENGTH() Function Works

In PostgreSQL, we can use the character_length() function to return the number of characters in a given string.

It accepts one argument; the string for which to return the length.

The character_length() function is a synonym for the char_length() function and so both do the same thing. We can also use the length() function to get the same result.

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Understanding STRING_TO_ARRAY() in PostgreSQL

In PostgreSQL, string_to_array() is a string function that allows us to create an array from a string. It splits the string based on the specified delimiter and returns a text array as a result.

If we specify a null delimiter, then each character becomes an element in the array. If the delimiter string is empty, then the whole string becomes a single element in the array.

We also have the option of turning a specific substring into null if required.

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A Brief Overview of SUBSTR() in PostgreSQL

In PostgreSQL, we can use the the substr() function to return a substring from a string, based on a starting point. We have the option of specifying how many characters to return.

We pass the string as the first argument and the start position as the second. If we want to specify how long the substring should be, we can pass a third argument that specifies how many characters to return.

The function returns the same result as the substring() function (which uses a slightly different syntax).

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A Quick Look at PostgreSQL’s REGEXP_LIKE() Function

In PostgreSQL, we can use the regexp_like() function to check whether or not a match of a POSIX regular expression occurs within a given string.

We pass the string as the first argument and the pattern as the second argument. We can also provide a flag as an optional third argument, which determines how the function behaves.

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