How the to_number() Function Works in PostgreSQL

In PostgreSQL, you can use the to_number() function to convert a string to a numeric value.

More specifically, it converts the string representation of a number to a numeric value.

For example, if you have $1,234.50 as a string, you can use to_number() to convert that to an actual number that uses the numeric data type.

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How to_timestamp() Works in PostgreSQL

According to the PostgreSQL documentation, there are two functions called to_timestamp():

  • One converts the Unix epoch to a timestamp. The Unix epoch is the number of seconds since 1970-01-01 00:00:00+00.
  • The other converts a string to a timestamp.

More specifically, each function converts the value to a timestamp with time zone value.

Although the Postgres documentation presents them as two separate to_timestamp() functions, I present them as if they’re one function that accepts either one argument, or two.

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How to_char() Works in PostgreSQL

In Postgres, to_char() is a data type formatting function that converts its first argument to a string.

The format of the string is determined by the second argument.

The to_char() function can be used to do the following conversions:

  • time stamp to string
  • interval to string
  • integer to string
  • real/double precision to string
  • numeric to string
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