Understanding the RIGHT() Function in PostgreSQL

In PostgreSQL the right() function returns the specified number of rightmost characters in a given string.

We have the option of specifying the number of characters to return from the right or the number of characters to omit from the left. We do this by specifying a positive integer (to return n number of rightmost characters) or a negative integer (to return everything except n leftmost characters).

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A Quick Look at the LEFT() Function in PostgreSQL

In PostgreSQL we can use the left() function to get the specified number of leftmost characters in a given string.

We have the option of specifying the number of characters to return from the left or the number of characters to omit from the right. We do this by specifying a positive integer (to return n number of leftmost characters) or a negative integer (to return everything except n rightmost characters).

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How REGEXP_REPLACE() Works in PostgreSQL

In PostgreSQL, we can use the regexp_replace() function to replace a substring within a given string, based on a given POSIX regular expression. We can specify that all matches are replaced or just the first match.

We pass the string as the first argument, the pattern as the second, and the replacement text as the third argument. We also have the option of specifying the start position as the fourth argument, and we can specify a flag to determine how the function behaves.

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