接口的使用
org.apache.shardingsphere.sql.parser.relation.segment.select.projection.Projection

使用Projection的程序包

程序包	说明
org.apache.shardingsphere.sql.parser.relation.segment.select.projection.engine
org.apache.shardingsphere.sql.parser.relation.segment.select.projection.impl

org.apache.shardingsphere.sql.parser.relation.segment.select.projection.engine中Projection的使用

返回变量类型为Projection的类型的org.apache.shardingsphere.sql.parser.relation.segment.select.projection.engine中的方法

限定符和类型	方法和说明
com.google.common.base.Optional<Projection>	ProjectionEngine.createProjection(String sql, SelectItemSegment selectItemSegment) Create projection.

org.apache.shardingsphere.sql.parser.relation.segment.select.projection.impl中Projection的使用

实现Projection的org.apache.shardingsphere.sql.parser.relation.segment.select.projection.impl中的类

限定符和类型	类和说明
class	AggregationDistinctProjection Aggregation distinct projection.
class	AggregationProjection Aggregation projection.
class	ColumnProjection Common projection.
class	DerivedProjection Derived projection.
class	ExpressionProjection Expression projection.
class	ShorthandProjection Shorthand projection.