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PDO Sqlite is truncating float #8510
Description
Description
The following code:
<?php
$pdo = new PDO('sqlite::memory:');
$pdo->exec('CREATE TABLE "types" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "float" DOUBLE PRECISION)');
$pdo->exec('insert into "types" ("float") values (10)');
$pdo->exec('update types set float = 8.202343767574732');
$stored = $pdo->query('select float from types limit 1')->fetchColumn(0);
var_dump($stored);
var_dump(bin2hex(pack('e', $stored)));
$pdo->exec('update types set float = \'8.202343767574732\'');
$stored = $pdo->query('select float from types limit 1')->fetchColumn(0);
var_dump($stored);
var_dump(bin2hex(pack('e', $stored)));Resulted in output with truncated float numbers, but I expected this output instead:
-string(16) "8.20234376757473"
+string(16) "8.202343767574732"
-string(16) "d790309a99672040"
+string(16) "d890309a99672040"
-string(16) "8.20234376757473"
+string(16) "8.202343767574732"
-string(16) "d790309a99672040"
+string(16) "d890309a99672040"demo: https://3v4l.org/5Qtf8
it is solely related with PDO Sqlite, PDO Mysql, PDO MSSQL, PDO PostgreSQL and PDO Oracle provide correct result
since PHP 8.1, a float Sqlite datatype is returned as a php float type and the result is correct
PHP Version
PHP 8.0
Operating System
any
Activity
cmb69 commentedon May 8, 2022
Is it? I mean this is about floating point numbers which are not (necessarily) exact.
Anyway, we won't backport 438b025 to PHP-8.0.
mvorisek commentedon May 8, 2022
yes, 64-bit IEEE 754 floating-point has specific precision
Although Sqlite does guarantee only 15 significant digits precision, 438b025#diff-6f85d6c531f4d77a70ce04f8bfcec3adc6679a0cd10b44b301f4e1107a41090cR285 line should be backported and the float casted to string with full precision. This way, string type for BC would be kept, but full precision would be returned.
mvorisek commentedon Oct 28, 2026
Good news! In SQLite v3.53.0 full precision is newly rendered:
source: https://www.sqlite.org/releaselog/3_53_0.html