Remove all zero dates from MySQL database across all Tables

Question

I have plenty of tables in MySQL which which contains zero date in dateTime column 0000-00-00 00:00:00

Using some sort of admin settings, Is it possibl

Answer 1

Prefix: You might want to check the concept of ETL in DataWareHousing, there are tools which should do the simple conversions for you, even Open Source ones like Kettle/Pentaho.

But this one is easy when you use any programming language capable of composing SQL queries. I have made an example in perl, but php or java would do also the job:

#!/usr/bin/perl

use strict;
use warnings;
use DBI;

my $user='geheim';
my $pass='secret';

my $dbh = DBI->connect( "dbi:mysql:host=localhost:database=to_convert:port=3306", $user, $pass ) or die $DBI::errstr;

# Prints out all the statements needed, might be checked before executed
my @tables = @{ $dbh->selectall_arrayref("show tables") };
  foreach my $tableh ( @tables){
    my $tabname = $tableh->[0];
    my $sth=$dbh->prepare("explain $tabname");
    $sth->execute();
    while (my $colinfo = $sth->fetchrow_hashref){
      if ($colinfo->{'Type'} =~ /date/i && $colinfo->{'Null'} =~ /yes/i){
        print ("update \`$tabname\` set \`" . $colinfo->{'Field'} . "\` = '1990-01-01' where \`" . $colinfo->{'Field'} . "\` IS NULL; \n");
        print ("alter table \`$tabname\` change column \`" . $colinfo->{'Field'} . "\`  \`" . $colinfo->{'Field'} . "\` " . $colinfo->{'Type'} . " not null default '1990-01-01'; \n");
      }
    }
  }

This does not change anything, but when the database has tables like:

localmysql [localhost]> explain dt;
+-------+------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+------+------+-----+---------+-------+
| a     | date | YES  |     | NULL    |       |
+-------+------+------+-----+---------+-------+
1 row in set (0.00 sec)

localmysql [localhost]> explain tst
    -> ;
+-------+----------+------+-----+---------+-------+
| Field | Type     | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+-------+
| id    | int(11)  | YES  |     | NULL    |       |
| atime | datetime | YES  |     | NULL    |       |
+-------+----------+------+-----+---------+-------+
2 rows in set (0.00 sec)

it produces the Statements:

update `dt` set `a` = '1990-01-01' where `a` IS NULL; 
alter table `dt` change column `a`  `a` date not null default '1990-01-01'; 
update `tst` set `atime` = '1990-01-01' where `atime` IS NULL; 
alter table `tst` change column `atime`  `atime` datetime not null default '1990-01-01'; 

This list can then be reviewed and executed as Statements.

Hope that Helps!