java.lang.Object
- org.hibernate.criterion.Projections

```
public final class Projections
extends Object
```
The criterion package may be used by applications as a framework for building new kinds of Projection. However, it is intended that most applications will simply use the built-in projection types via the static factory methods of this class. The factory methods that take an alias allow the projected value to be referred to by criterion and order instances. See also the Restrictions factory methods for generating Criterion instances

作者:

Gavin King, Steve Ebersole

另请参阅:

Criteria

方法概要

所有方法静态方法具体方法
修饰符和类型	方法	说明
`static Projection`	`alias(Projection projection, String alias)`	Assign an alias to a projection, by wrapping it
`static AggregateProjection`	`avg(String propertyName)`	A property average value projection
`static CountProjection`	`count(String propertyName)`	A property value count projection
`static CountProjection`	`countDistinct(String propertyName)`	A distinct property value count projection
`static Projection`	`distinct(Projection projection)`	Create a distinct projection from a projection.
`static PropertyProjection`	`groupProperty(String propertyName)`	A grouping property value projection
`static IdentifierProjection`	`id()`	An identifier value projection.
`static AggregateProjection`	`max(String propertyName)`	A property maximum value projection
`static AggregateProjection`	`min(String propertyName)`	A property minimum value projection
`static ProjectionList`	`projectionList()`	Create a new projection list.
`static PropertyProjection`	`property(String propertyName)`	A property value projection
`static Projection`	`rowCount()`	The query row count, ie.
`static Projection`	`sqlGroupProjection(String sql, String groupBy, String[] columnAliases, Type[] types)`	A grouping SQL projection, specifying both select clause and group by clause fragments
`static Projection`	`sqlProjection(String sql, String[] columnAliases, Type[] types)`	A SQL projection, a typed select clause fragment
`static AggregateProjection`	`sum(String propertyName)`	A property value sum projection

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 方法详细资料
  - property
```
public static PropertyProjection property(String propertyName)
```
    A property value projection
    
    参数:
    
    propertyName - The name of the property whose values should be projected
    
    返回:
    
    The property projection
    
    另请参阅:
    
    PropertyProjection
  - groupProperty
```
public static PropertyProjection groupProperty(String propertyName)
```
    A grouping property value projection
    
    参数:
    
    propertyName - The name of the property to group
    
    返回:
    
    The grouped projection
    
    另请参阅:
    
    PropertyProjection
  - id
```
public static IdentifierProjection id()
```
    An identifier value projection.
    
    返回:
    
    The identifier projection
    
    另请参阅:
    
    IdentifierProjection
  - distinct
```
public static Projection distinct(Projection projection)
```
    Create a distinct projection from a projection.
    
    参数:
    
    projection - The project to treat distinctly
    
    返回:
    
    The distinct projection
    
    另请参阅:
    
    Distinct
  - projectionList
```
public static ProjectionList projectionList()
```
    Create a new projection list.
    
    返回:
    
    The projection list
  - rowCount
```
public static Projection rowCount()
```
    The query row count, ie. count(*)
    
    返回:
    
    The projection representing the row count
    
    另请参阅:
    
    RowCountProjection
  - count
```
public static CountProjection count(String propertyName)
```
    A property value count projection
    
    参数:
    
    propertyName - The name of the property to count over
    
    返回:
    
    The count projection
    
    另请参阅:
    
    CountProjection
  - countDistinct
```
public static CountProjection countDistinct(String propertyName)
```
    A distinct property value count projection
    
    参数:
    
    propertyName - The name of the property to count over
    
    返回:
    
    The count projection
    
    另请参阅:
    
    CountProjection
  - max
```
public static AggregateProjection max(String propertyName)
```
    A property maximum value projection
    
    参数:
    
    propertyName - The property for which to find the max
    
    返回:
    
    the max projection
    
    另请参阅:
    
    AggregateProjection
  - min
```
public static AggregateProjection min(String propertyName)
```
    A property minimum value projection
    
    参数:
    
    propertyName - The property for which to find the min
    
    返回:
    
    the min projection
    
    另请参阅:
    
    AggregateProjection
  - avg
```
public static AggregateProjection avg(String propertyName)
```
    A property average value projection
    
    参数:
    
    propertyName - The property over which to find the average
    
    返回:
    
    the avg projection
    
    另请参阅:
    
    AvgProjection
  - sum
```
public static AggregateProjection sum(String propertyName)
```
    A property value sum projection
    
    参数:
    
    propertyName - The property over which to sum
    
    返回:
    
    the sum projection
    
    另请参阅:
    
    AggregateProjection
  - alias
```
public static Projection alias(Projection projection,
                               String alias)
```
    Assign an alias to a projection, by wrapping it
    
    参数:
    
    projection - The projection to be aliased
    
    alias - The alias to apply
    
    返回:
    
    The aliased projection
    
    另请参阅:
    
    AliasedProjection
  - sqlProjection
```
public static Projection sqlProjection(String sql,
                                       String[] columnAliases,
                                       Type[] types)
```
    A SQL projection, a typed select clause fragment
    
    参数:
    
    sql - The SQL fragment
    
    columnAliases - The column aliases
    
    types - The resulting types
    
    返回:
    
    The SQL projection
    
    另请参阅:
    
    SQLProjection
  - sqlGroupProjection
```
public static Projection sqlGroupProjection(String sql,
                                            String groupBy,
                                            String[] columnAliases,
                                            Type[] types)
```
    A grouping SQL projection, specifying both select clause and group by clause fragments
    
    参数:
    
    sql - The SQL SELECT fragment
    
    groupBy - The SQL GROUP BY fragment
    
    columnAliases - The column aliases
    
    types - The resulting types
    
    返回:
    
    The SQL projection
    
    另请参阅:
    
    SQLProjection

类 Projections

方法概要

从类继承的方法 java.lang.Object

方法详细资料

property

groupProperty

id

distinct

projectionList

rowCount

count

countDistinct

max

min

avg

sum

alias

sqlProjection

sqlGroupProjection