To convert a date to a hexadecimal (hex) value in MySQL, you can use the `HEX()`

function. The `HEX()`

function is used to return a string representation of a hexadecimal value.

Here is the general syntax to convert a date to hex in MySQL:

1 2 |
SELECT HEX(date_column) AS hex_date FROM your_table; |

Here, `date_column`

refers to the column name of the date you want to convert, and `your_table`

is the table name.

For example, if you have a table called "users" with a column named "birth_date" containing dates, and you want to convert the birth dates to hex values:

1 2 |
SELECT HEX(birth_date) AS hex_date FROM users; |

This query will return the hexadecimal representation of the birth date values in the "birth_date" column as "hex_date" in the result set.

It's important to note that the `HEX()`

function converts the date to a string representation of its binary value, which is then displayed as a hexadecimal string.

## How to convert a string to a boolean in MySQL?

In MySQL, you can use the `CAST`

or `CONVERT`

function to convert a string to a Boolean value. MySQL treats the string '0' as false and any other non-empty string as true.

Here are a few examples:

- Using the CAST function:

1 2 3 4 |
SELECT CAST('true' AS BOOLEAN); -- returns 1 (true) SELECT CAST('false' AS BOOLEAN); -- returns 0 (false) SELECT CAST('1' AS BOOLEAN); -- returns 1 (true) SELECT CAST('0' AS BOOLEAN); -- returns 0 (false) |

- Using the CONVERT function:

1 2 3 4 |
SELECT CONVERT('true', BOOLEAN); -- returns 1 (true) SELECT CONVERT('false', BOOLEAN); -- returns 0 (false) SELECT CONVERT('1', BOOLEAN); -- returns 1 (true) SELECT CONVERT('0', BOOLEAN); -- returns 0 (false) |

Note that if the string is empty or contains non-numeric characters besides '0', it will be converted to 0 (false) using these methods.

## How to convert a hex to octal in MySQL?

In MySQL, you can convert a hexadecimal number to an octal number using the `CONV()`

function. The `CONV()`

function accepts three arguments: the number to convert, the current base of the number, and the desired base to convert to.

Here's an example of converting a hexadecimal number to an octal number in MySQL:

```
1
``` |
```
SELECT CONV('1A', 16, 8) AS octal_number;
``` |

In this example, `'1A'`

is the hexadecimal number we want to convert. The second argument `16`

indicates that the current base is hexadecimal. The third argument `8`

specifies that we want to convert it to octal.

The result would be `32`

, which is the octal representation of the hexadecimal number `'1A'`

.

## How to convert a binary to octal in MySQL?

In MySQL, you can use the `CONV()`

function to convert a binary value to an octal value.

The syntax of the `CONV()`

function is as follows:

```
1
``` |
```
CONV(number, from_base, to_base)
``` |

To convert a binary value to octal, you would specify the `from_base`

as 2 (binary) and the `to_base`

as 8 (octal). Here is an example:

```
1
``` |
```
SELECT CONV('11010110', 2, 8) AS octal_value;
``` |

This will return the octal representation of the binary value '11010110', which is '326' in octal. The result will be displayed as:

1 2 3 4 5 |
+-------------+ | octal_value | +-------------+ | 326 | +-------------+ |

So, the binary value '11010110' is equivalent to the octal value '326'.

## How to convert a character to lowercase in MySQL?

In MySQL, you can use the `LOWER()`

function to convert a character or a string to lowercase. Here is how you can use it:

```
1
``` |
```
SELECT LOWER('YourCharacter');
``` |

Replace `'YourCharacter'`

with the character or string you want to convert. The function will return the lowercase version of the input.

## How to convert a decimal to scientific notation in MySQL?

MySQL does not have built-in functions to directly convert a decimal to scientific notation. However, you can manually convert a decimal to scientific notation using string manipulation and mathematical operations.

Here's an example of how you can convert a decimal to scientific notation in MySQL:

- Extract the exponent of the number by using the logarithm base 10. You can do this by using the LOG10() function in MySQL.

```
1
``` |
```
SELECT LOG10(abs(number)) AS exponent FROM your_table;
``` |

- Round the exponent to the nearest integer using the ROUND() function.

```
1
``` |
```
SELECT ROUND(LOG10(abs(number))) AS rounded_exponent FROM your_table;
``` |

- Divide the original number by 10 raised to the power of the rounded exponent to get the mantissa part of the scientific notation.

```
1
``` |
```
SELECT number / POW(10, ROUND(LOG10(abs(number)))) AS mantissa FROM your_table;
``` |

- Concatenate the mantissa and exponent parts with 'e' to get the final scientific notation.

```
1
``` |
```
SELECT CONCAT(mantissa, 'e', rounded_exponent) AS scientific_notation FROM your_table;
``` |

Replace `number`

with the actual column or value you want to convert. Replace `your_table`

with the actual table name or table expression.

Please note that this method will only provide a basic conversion to scientific notation and may not handle all possible scenarios.