In case anyone has seen spurious problems using MySQL version 5.0.32 (and presumably the identical 5.0.33 community version) you might want to take a look at MySQL Bugs #25653 and #25596. They are about a little (but serious) InnoDB bug.

If you do not yet use this version, you might consider waiting for a fixed release to become available.

In case anyone has seen spurious problems using MySQL version 5.0.32 (and presumably the identical 5.0.33 community version) you might want to take a look at MySQL Bugs #25653 and #25596. They are about a little (but serious) InnoDB bug.

If you do not yet use this version, you might consider waiting for a fixed release to become available.

Last week I needed to write an update SQL script that would insert some records into a database. However as the script was to be incorporated into a software update that was going to be deployed to all our customers, it needed to check some condition first and see, whether the insert was required at all.

Even though MySQL provides some non-standard SQL enhancement there is no INSERT IF EXISTS kind of statement.

I managed to do it using some temp-tables and a combination of INSERT IGNORE ... SELECT FROM and UPDATE ... WHERE statements.

The following example demonstrates how to insert a new row of data in the table named real_table. The data must only be inserted into this table, if another record in a table named condition_table exists. No change of real_table must occur, if there is no record matching the condition.

Moreover (because I …

Last week I needed to write an update SQL script that would insert some records into a database. However as the script was to be incorporated into a software update that was going to be deployed to all our customers, it needed to check some condition first and see, whether the insert was required at all.

Even though MySQL provides some non-standard SQL enhancement there is no INSERT IF EXISTS kind of statement.

I managed to do it using some temp-tables and a combination of INSERT IGNORE ... SELECT FROM and UPDATE ... WHERE statements.

The following example demonstrates how to insert a new row of data in the table named real_table. The data must only be inserted into this table, if another record in a table named condition_table exists. No change of real_table must occur, if there is no record matching the condition.

Moreover (because I …

I mentioned when grant statements take into effect in Sql Server, MySql, and Oracle here.

I found out recently that there are some implementation differences when you grant only delete permission on a table to a user. MySql and Sql Server do this the same way, whereas Oracle is different.

Suppose you have:

1. Table t1: create table t1 (c1 int);
2. User TestLogin. The only permission of this TestLogin is delete on t1.

In all 3 database platforms, TestLogin can find out what columns t1 has by default, using either

desc t1

or

sp_columns t1

In both Sql Server and MySql, the only thing you can do is:

delete from t1;

which essentially wipes out the whole table. You can do the same thing in Oracle.

However, if you do:

…

After some time here is another post concerning MySQL. It is not as if I had not had anything to do with MySQL in the meantime, but most of it was mailing back and forth with their customer support (which is really quite good) to get some issues resolved we stumbled over in our MySQL 4.1 to 5.0 migration.

Before those were fixed we could not use MySQL 5 with our application, because there were some incompatible changes we could not work around.

One of them was the unsatisfactory precision when querying DECIMALs I wrote about earlier. This is fixed in 5.0.32-enterprise and the just released 5.0.33 community edition (see Bug #23260). In fact I was just about to write about the new release policy which I find somewhat strange (enterprise and community editions with the …

After some time here is another post concerning MySQL. It is not as if I had not had anything to do with MySQL in the meantime, but most of it was mailing back and forth with their customer support (which is really quite good) to get some issues resolved we stumbled over in our MySQL 4.1 to 5.0 migration.

Before those were fixed we could not use MySQL 5 with our application, because there were some incompatible changes we could not work around.

One of them was the unsatisfactory precision when querying DECIMALs I wrote about earlier. This is fixed in 5.0.32-enterprise and the just released 5.0.33 community edition (see Bug #23260). In fact I was just about to write about the new release policy which I find somewhat strange (enterprise and community editions with the …

In both Sql Server and Oracle, permission changes to a user take into effect right away, even when said user is connected at the time you made the change.

In MySql, it is a little different, depending on how the permissions are given. If you use the GRANT statement, then it takes into effect right away. However, if you create user and give it permissions by manipulating the user table in the mysql system database directly, that is, using Sql statements, then you need to issue:

flush privileges

for those changes to be picked up.

Sql Server 2005 has a command line tool named sqlcmd. MySQL has a command line tool named mysql. Oracle has a command line tool called sqlplus. They can all be used for interactive query processing and batch scripts processing. They do similar things, albeit in different ways. They are functionally equivalent.

For Sql Server 2005, when in interactive mode of sqlcmd, use

:r c:MyFolderMyScript.sql

to read and execute a script file. You may have to type

go

afterwards, if the last line of the script file does not end with the word go.

To use sqlcmd in batch mode, that is, to run a sql script and then get out, use:

sqlcmd -i c:MyFolderMyScript.sql -S MyServerName -E

Replace -E with -U LoginName if you use Sql authentication

For MySQL, while in interactive mode of mysql, use

. c:MyFolderMyScript.sql (on Windows)

Note there should be a backward …

In Oracle and MySql, to get the column name and data type of a table, you can use:

desc MyTable

or

describe MyTable

The equivalent of desc in Sql Server is sp_columns. Therefore, run the command below will get similar results:

sp_columns MyTable