PHP PDO issue with float data type

[phanxgames]

When querying data from a Dolt database (version 0.40.16) using the PHP PDO library (version: PHP Version 7.2.24, PDO: mysqlnd 5.0.12-dev), I found that the float values were being rounded (mostly). Double and decimal are working as expected.

PDO+dolt Results:

Expected Value	Output: float	Output: double	Output: decimal(5,4)
0.5	0	0.5	0.5000
0.0006	0	0.0006	0.0006
-1.5	-2	-1.5	-1.5000
1.5	2	1.5	1.5000
1.2	1	1.2	1.2000

In conclusion the test results of various combinations within PHP:

• PDO+dolt = failure
• PDO+mariadb = success
• mysqli+dolt = success

After much trial and error I did find one PDO setting that makes the PDO+dolt work, but this is not on by default, and the PDO+mariadb did not require it.

$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, true);

At least the above setting allows us to work around this issue, and hopefully anyone else that has the similar issue can try it out as well.

[timsehn]

Thanks for the issue and repro. We'll try and match the expected behavior.

[jennifersp]

Hi @phanxgames, thank you for the issue. I was not able to reproduce this issue. Can you give us little more details on the queries you ran to get this issue?

So far, I have tried running with and without defining PDO::ATTR_EMULATE_PREPARES, I get the expected results for having PDO::ATTR_EMULATE_PREPARES undefined or defined it as true. I was able to get this rounded float data type result only when PDO::ATTR_EMULATE_PREPARES was defined as false. I've also tried with prepared statements using PDO's prepare method, and it gives expected results regardless of defining PDO::ATTR_EMULATE_PREPARES.

Please let me know if I'm missing or misunderstanding something here.

[timsehn]

I'm going to close since we can't repro. Reopen if you can provide more information.