MySQL，如何插入null日期

Question

I am having trouble inserting null values into date fields into a MySQL table.

Here is the insert query:

$query = 'INSERT INTO table (column_s1, column_s2, column_d1, column_d2)
VALUES ("'.$string1.'", "'.$string2.'", '.$date1.', '.$date2.')';

Columns s1 and s2 take string values and d1 and d2 take dates. When I run this query with only the string fields, there is no problem.

The date values can be either set or null, so I have not included the quotation marks in the query, but have instead added them to the variable earlier on. This is the php code I am using to set the date values:

if (empty($date1)){
    $date1 = NULL;
}
else{
    $date1part = explode("/",$date1);
    $date1 = '"'.$date1part[2].'/'.$date1part[1].'/'.$date1part[0].'"';
}

When the date values are all set, the record is inserted correctly. However, when either of the dates is null, nothing is inserted.

Why can't I just insert null values into MySQL like this?

Answer 1

Try this:

$query = "INSERT INTO table (column_s1, column_s2, column_d1, column_d2) 
          VALUES ('$string1', '$string2', " . ($date1==NULL ? "NULL" : "'$date1'") . ", " . ($date2==NULL ? "NULL" : "'$date2'") . ");";

so for example if you put this into query:

$string1 = "s1";
$string2 = "s2";
$date1 = NULL;
$date2 = NULL;

result should be:

INSERT INTO table (column_s1, column_s2, column_d1, column_d2) VALUES ('s1', 's2', NULL, NULL);

Answer 2

You should convert the null variable into a NULL string first Like this:

if(is_null($date1)){
    $date1 = 'NULL';
}

If you are using a MySQL date column, you must also specify that it should hold null when creating it, like this:

CREATE TABLE `table` (
id INT NOT NULL AUTO_INCREMENT,
date DATE NULL DEFAULT NULL,
PRIMARY KEY(id)
)

It is also very important that you perform the query with bound parameters, for example using pdo

1. http://www.php.net/manual/en/pdo.construct.php
2. http://php.net/manual/en/pdo.prepared-statements.php
3. How do I insert NULL values using PDO?

Something like this:

$query = 'INSERT INTO table (column_s1, column_s2, column_d1, column_d2)
VALUES (?, ?, ?, ?)';
$stmt = $db->prepare($query);
$stmt->execute(array($string1,$string2,$date1,$date2));

Answer 3

Backslash N is another way to express NULL in MySQL.

Try putting the value (backslash N): \\N into one of the parameters like this:

$data1 = "\N";
$sql="insert into tablename set column_s1='" . $data1 . 
  "', column_s2='" . data2 . 
  "', column_s3='" . $data3 . "'";

Reference: http://dev.mysql.com/doc/refman/5.1/en/load-data.html

Answer 4

如果 NULL 不起作用，只需将您的日期传递为“0000-00-00”：

$chequeDate = "0000-00-00";

Answer 5

在 Derby 中，如果要插入除已声明为 Null (column_d1, column_d2) 之外的值，sql：

INSERT INTO DB.table (column_s1, column_s2) VALUES ('s1', 's2');

Answer 6

Probably answer is unneeded at this moment, but I found solution exactly I have been searching. Use an Expression to pass NULL like this:

['some_date_to_update' => new Expression('NULL')]

Hence, MySQL will understand what you want, and save (NULL) in DB instead of storing 0-dates. Hope this will help somebody.

Answer 7

In Mysql DATE data type Default NULL means

Some version set as 0000-00-00

Some version set as 1970-01-01

Answer 8

Years later, if someone is still experiencing this issue, you want to use PDO and bind the variables, everything will be taken care of no need to handle the null variables yourself.