fix(mysql): fix databend float64 to mysql double

[FANNG1]

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Summary

Summary about this PR

Closes #issue

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1 Ignored Deployment

Name	Status	Preview	Updated
databend	⬜️ Ignored (Inspect)		Nov 11, 2022 at 9:53AM (UTC)

[FANNG1]

cc @sundy-li

[FANNG1]

@mergify update

[mergify]

update

☑️ Nothing to do

• #commits-behind>0 [:pushpin: update requirement]
• -closed [:pushpin: update requirement]

[FANNG1]

BTW, all of databend integers are converted to MYSQL_TYPE_LONG, is this the expected behavior?

                TypeID::Int8 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::Int16 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::Int32 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::Int64 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::UInt8 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::UInt16 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::UInt32 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::UInt64 => Ok(ColumnType::MYSQL_TYPE_LONG),

[xudong963]

BTW, all of databend integers are converted to MYSQL_TYPE_LONG, is this the expected behavior?

                TypeID::Int8 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::Int16 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::Int32 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::Int64 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::UInt8 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::UInt16 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::UInt32 => Ok(ColumnType::MYSQL_TYPE_LONG),
                TypeID::UInt64 => Ok(ColumnType::MYSQL_TYPE_LONG),

I think it doesn't matter(no loss of precision).

[FANNG1]

MYSQL_TYPE_LONG is 32bit not 64, seems we should use 'MYSQL_LONGLONG' for TypeID::Int64&uint64

[FANNG1]

I think it doesn't matter(no loss of precision).

for me， I shoud pass databend data to hive， if I get query a small int column, databend produces long while hive expected small int, there maybe some problems. so I prefer to correct it like https://dev.mysql.com/doc/c-api/8.0/en/c-api-prepared-statement-type-codes.html.