> ## Documentation Index
> Fetch the complete documentation index at: https://docs.regatta.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Type Conversion

Type conversion can happen in the following cases:

1. When mixing different data types while combining two result sets with `UNION`.
2. When passing to functions and operators, operands of different types than their input operand types.
3. When assigning values of different types to table row cells.

In these cases, either Regatta implicitly converts them into a data type that allows the operation to continue, or they can be explicitly converted into the desired data type using the general [Convert Function](/sql/sql-functions-and-operators/convert-function) or the type-specific conversion functions listed in the table below.

The following rules apply to type conversions:

1. When combining queries (`UNION` \[`ALL`]), Regatta converts the data types of both queries to the “larger” data type of them.

   E.g: During `UNION` on two queries, if the first returns `DATE` and the other returns `TIMESTAMP`, Regatta converts the `DATE` into `TIMESTAMP`.
2. When converting strings to other data types, the conversion fails if the string is not a valid representation of the value of the target type.

   For example, conversion of '3' to Integer would succeed but conversion of 'ttt' or '3.1' to integer would fail.
3. When converting from `FLOAT4/8` or `DECIMAL` to integers, the value is rounded to the closest integer.
4. During `INSERT` and `UPDATE` operations, Regatta converts the value to the datatype of the affected column. If the value is too large for the target data type, the operation fails.
5. Conversion from `TIMESTAMP` to `DATE` or `TIME` extracts the relevant part of the `TIMESTAMP` into the target element.

   E.g: `SELECT '2023-12-12 23:00:05'::time` returns `23:00:05`.
6. When converting integral types to `BOOLEAN`, `0` is converted to `FALSE` and any other value is converted to `TRUE`.
7. Any conversion (explicit or implicit) to a numeric type (integers, floating point and decimals) would fail if the value cannot fit within the range of the target type.

   For example, `SELECT 1234567::SMALLINT` will fail since the value is out of the `SMALLINT` range.
8. Explicit conversion to [Character types](/sql/data-types/character-types) trims the converted string to fit the size of the target type, however, implicit conversion would not trim the text and would result in an error.

   For example: `CAST(150 as CHAR(2))` returns `15` but assigning `150` to a `CHAR(2)` column without explicit casting would fail.
9. `CHAR` types are implicitly converted to `VARCHAR` (and the trailing spaces are trimmed) when they are used as inputs to any function/operation.

   For example: Comparison of `VARCHAR(10)` containing the value `‘Regatta’` and `CHAR(10)` containing the value `‘Regatta   ’` results in `TRUE`.

   Note: If the `VARCHAR` contains trailing spaces as part of its string, the comparison will return `FALSE`. For example: `CHAR(10)` with the text `'Regatta'` is not equal to `VARCHAR(10)` with the text `'Regatta '`.