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Cast expressions
Applies to ✅ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
jOOQ's source code generator tries to find the most accurate type mapping between your vendor-specific data types and a matching Java type. For instance, most VARCHAR, CHAR, CLOB types will map to String. Most BINARY, BYTEA, BLOB types will map to byte[]. NUMERIC types will default to java.math.BigDecimal, but can also be any of java.math.BigInteger, java.lang.Long, java.lang.Integer, java.lang.Short, java.lang.Byte, java.lang.Double, java.lang.Float.
Sometimes, this automatic mapping might not be what you needed, or jOOQ cannot know the type of a field. In those cases you would write SQL type CAST like this:
-- Let's say, your Postgres column LAST_NAME was VARCHAR(30) -- Then you could do this: SELECT CAST(AUTHOR.LAST_NAME AS TEXT) FROM DUAL
in jOOQ, you can write something like that:
create.select(AUTHOR.LAST_NAME.cast(VARCHAR(100))).fetch();
The complete CAST API in org.jooq.Field consists of these three methods:
public interface Field<T> {
// Cast this field to the type of another field
<Z> Field<Z> cast(Field<Z> field);
// Cast this field to a given DataType
<Z> Field<Z> cast(DataType<Z> type);
// Cast this field to the default DataType for a given Class
<Z> Field<Z> cast(Class<? extends Z> type);
}
// And additional convenience methods in the DSL:
public class DSL {
<T> Field<T> cast(Object object, Field<T> field);
<T> Field<T> cast(Object object, DataType<T> type);
<T> Field<T> cast(Object object, Class<? extends T> type);
<T> Field<T> castNull(Field<T> field);
<T> Field<T> castNull(DataType<T> type);
<T> Field<T> castNull(Class<? extends T> type);
}
The CAST expression converts between data types directly in SQL. If you wish to change a data type without any effect on rendered SQL, you may prefer to coerce your expressions.
Dialect support
This example using jOOQ:
cast("1", VARCHAR(10))
Translates to the following dialect specific expressions:
Access
cstr('1')
ASE, Aurora Postgres, DB2, Derby, DuckDB, Exasol, Firebird, H2, HSQLDB, Hana, Postgres, Redshift, SQLDataWarehouse, SQLServer, SQLite, Snowflake, Sybase, Teradata, Trino, Vertica, YugabyteDB
CAST('1' AS varchar(10))
Aurora MySQL, MariaDB, MemSQL, MySQL
CAST('1' AS char(10))
BigQuery
CAST('1' AS string)
ClickHouse
CAST('1' AS String(10))
CockroachDB
CAST('1' AS string(10))
Informix
CAST('1' AS lvarchar(10))
Oracle
CAST('1' AS varchar2(10))
Generated with jOOQ 3.20. Translate your own SQL on our website
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