Querying Unix Timestamp using JOOQ - mysql

Question

I'm using a MySQL server, and I'm trying to retrieve a timestamp using the JOOQ API. However, I think the default JOOQ behavior returns the time in the local timezone, and not UTC (it's not using UNIX_TIMESTAMP(). Using JOOQ, my query looks like
db.select(USER_TABLE.REGISTERED_ON)
.from(USER_TABLE)
.where(USER_TABLE.EMAIL.equal(email)
.fetchAny()
However, the sql that I want to execute should be something like this
SELECT UNIX_TIMESTAMP(schema.table.timestamp_col)
FROM schema.table
WHERE email="someone#domain.com"
Is it possible using the JOOQ API? If not, what's the best way to run this query, because I really want to be able to use the generated code (USER_TABLE, USER_TABLE.REGISTERED_ON, etc).
EDIT: I'm now doing the following, but is it safe? Basically I'm removing the quotations from JOOQ's generated classes.
String timestamp_field = USER_TABLE.REGISTERED_ON.toString().replace("\"", "");
Field<?> f = DSL.field("UNIX_TIMESTAMP(" + timestamp_field + ")");
Record r = db.select(f)
.from(USER_TABLE)
.where(USER_TABLE.EMAIL.equal(email))
.fetchAny();

Answer 1

There are several ways to tackle this problem:
Use a Converter or Binding to convert the type
You can register a data type Converter or Binding in the source code generator. This way, the code generator will generate a Field<YourType> for every TIMESTAMP field in the database. Possible useful types are:
java.lang.Long
java.time.Instant
java.time.OffsetDateTime (note that jOOQ 3.7 will support this via [#4338])3
Use plain SQL
Use plain SQL every time you want to do an explicit conversion using the UNIX_TIMESTAMP() function. Your solution works:
String timestamp_field = USER_TABLE.REGISTERED_ON.toString().replace("\"", "");
Field<?> f = DSL.field("UNIX_TIMESTAMP(" + timestamp_field + ")");
But it is not recommended because:
You should never rely on any toString() implementation of any Java type.
You should generally try to avoid string concatenation with jOOQ's plain SQL API
A better solution would be:
DSL.field("UNIX_TIMESTAMP({0})", Long.class, USER_TABLE.REGISTERED_ON);
Or even:
public static Field<Long> unixTimestamp(Field<Timestamp> arg) {
return DSL.field("UNIX_TIMESTAMP({0})", Long.class, arg);
}
Use BIGINT in the database
You could of course use BIGINT or BIGINT UNSIGNED in the database instead of TIMESTAMP. This way, you will always automatically have the integer unix timestamp value. This is just a workaround for completeness's sake.