I need to add an interval to a date (both columns are in a table) using MySQL and JPA Criteria. I know the following functions are required:
MySQL's DATE_ADD:
DATE_ADD(date,INTERVAL expr unit)
CriteriaBuilder's function:
function(String name, Class<T> type, Expression<?>... args)
I also have a class to create function expressions:
public class SqlFunctionExpression extends BasicFunctionExpression<String> implements Serializable {
public SqlFunctionExpression(CriteriaBuilderImpl criteriaBuilder,
Class<String> javaType,
String functionName) {
super(criteriaBuilder, javaType, functionName);
}
@Override
public String render(RenderingContext renderingContext) {
return getFunctionName();
}
}
which can be used like new SqlFunctionExpression(null, String.class, "MINUTE") to create a minute unit.
However, how do I create the expression INTERVAL expr unit where expr is a table column?
or we can directly do date add from java side and send that as argument for comparison like so
criteriaBuilder.equal(exceptionsJoinOnRoot.get(MyModelClass_.tartDate),
Date.from(LocalDate.now().atStartOfDay(ZoneId.systemDefault()).plus(Period.ofDays(1))
.toInstant()))
if this doesn't work we can use ADDDATE mysql function
criteriaBuilder.equal(exceptionsJoinOnRoot.get(MyModelClass_.tartDate),
criteriaBuilder.function("ADDDATE",Date.class,criteraBuilder.currentTimestamp(),criteriaBuilder.literal(1)))
Register function
public class CommonMySQLDialect extends MySQL57Dialect {
public CommonMySQLDialect() {
super();
registerFunction("date_add", new SQLFunctionTemplate(TimestampType.INSTANCE, "date_add(?1, INTERVAL ?2 ?3)"));
}
}
Add to hibernate configuration
<property name="hibernate.dialect">yourpackage.CommonMySQLDialect</property>
Ready to use
Expression<String> unit = new SqlFunctionExpression(null, String.class, "MINUTE");
Expression<Integer> num = cb.literal(10);
Expression<Date> newDate = cb.function("date_add", Date.class, cb.currentTimestamp(), num, unit);
To pass through raw tokens like INTERVAL 1 YEAR through to MySQL, you can use my OpaqueLiteralExpression class which is described here: https://stackoverflow.com/a/69998155/263801