Package org.h2.expression.aggregate

Class Aggregate

java.lang.Object
org.h2.expression.Expression
org.h2.expression.analysis.DataAnalysisOperation
org.h2.expression.aggregate.AbstractAggregate
org.h2.expression.aggregate.Aggregate
All Implemented Interfaces:
ExpressionWithFlags, HasSQL, Typed
public class Aggregate extends AbstractAggregate implements ExpressionWithFlags
Implements the integrated aggregate functions, such as COUNT, MAX, SUM.

  • Constructor Details

    • Aggregate

      public Aggregate(AggregateType aggregateType, Expression[] args, Select select, boolean distinct)
      Create a new aggregate object.
      Parameters:
      aggregateType - the aggregate type
      args - the aggregated expressions
      select - the select statement
      distinct - if distinct is used

  • Method Details

    • getAggregateType

      public static AggregateType getAggregateType(String name)
      Get the aggregate type for this name, or -1 if no aggregate has been found.
      Parameters:
      name - the aggregate function name
      Returns:
      null if no aggregate function has been found, or the aggregate type

    • setOrderByList

      public void setOrderByList(ArrayList<QueryOrderBy> orderByList)
      Set the order for ARRAY_AGG() or GROUP_CONCAT() aggregate.
      Parameters:
      orderByList - the order by list

    • getAggregateType

      public AggregateType getAggregateType()
      Returns the type of this aggregate.
      Returns:
      the type of this aggregate

    • setExtraArguments

      public void setExtraArguments(Object extraArguments)
      Sets the additional arguments.
      Parameters:
      extraArguments - the additional arguments

    • getExtraArguments

      public Object getExtraArguments()
      Returns the additional arguments.
      Returns:
      the additional arguments

    • setFlags

      public void setFlags(int flags)
      Description copied from interface: ExpressionWithFlags
      Set the flags for this expression.
      Specified by:
      setFlags in interface ExpressionWithFlags
      Parameters:
      flags - the flags to set

    • getFlags

      public int getFlags()
      Description copied from interface: ExpressionWithFlags
      Returns the flags.
      Specified by:
      getFlags in interface ExpressionWithFlags
      Returns:
      the flags

    • updateAggregate

      protected void updateAggregate(SessionLocal session, Object aggregateData)
      Description copied from class: AbstractAggregate
      Updates an aggregate value.
      Specified by:
      updateAggregate in class AbstractAggregate
      Parameters:
      session - the session
      aggregateData - aggregate data

    • updateGroupAggregates

      protected void updateGroupAggregates(SessionLocal session, int stage)
      Description copied from class: DataAnalysisOperation
      Invoked when processing group stage of grouped window queries to update arguments of this aggregate.
      Overrides:
      updateGroupAggregates in class AbstractAggregate
      Parameters:
      session - the session
      stage - select stage

    • getNumExpressions

      protected int getNumExpressions()
      Description copied from class: DataAnalysisOperation
      Returns the number of expressions, excluding OVER clause.
      Specified by:
      getNumExpressions in class DataAnalysisOperation
      Returns:
      the number of expressions

    • rememberExpressions

      protected void rememberExpressions(SessionLocal session, Value[] array)
      Description copied from class: DataAnalysisOperation
      Stores current values of expressions into the specified array.
      Specified by:
      rememberExpressions in class DataAnalysisOperation
      Parameters:
      session - the session
      array - array to store values of expressions

    • updateFromExpressions

      protected void updateFromExpressions(SessionLocal session, Object aggregateData, Value[] array)
      Description copied from class: AbstractAggregate
      Updates the provided aggregate data from the remembered expressions.
      Specified by:
      updateFromExpressions in class AbstractAggregate
      Parameters:
      session - the session
      aggregateData - aggregate data
      array - values of expressions

    • createAggregateData

      protected Object createAggregateData()
      Description copied from class: DataAnalysisOperation
      Create aggregate data object specific to the subclass.
      Specified by:
      createAggregateData in class DataAnalysisOperation
      Returns:
      aggregate-specific data object.

    • getValue

      public Value getValue(SessionLocal session)
      Description copied from class: Expression
      Return the resulting value for the current row.
      Overrides:
      getValue in class DataAnalysisOperation
      Parameters:
      session - the session
      Returns:
      the result

    • getAggregatedValue

      public Value getAggregatedValue(SessionLocal session, Object aggregateData)
      Description copied from class: DataAnalysisOperation
      Returns aggregated value.
      Specified by:
      getAggregatedValue in class DataAnalysisOperation
      Parameters:
      session - the session
      aggregateData - the aggregate data
      Returns:
      aggregated value.

    • mapColumnsAnalysis

      public void mapColumnsAnalysis(ColumnResolver resolver, int level, int innerState)
      Description copied from class: DataAnalysisOperation
      Map the columns of the resolver to expression columns.
      Overrides:
      mapColumnsAnalysis in class AbstractAggregate
      Parameters:
      resolver - the column resolver
      level - the subquery nesting level
      innerState - one of the Expression MAP_IN_* values

    • optimize

      public Expression optimize(SessionLocal session)
      Description copied from class: Expression
      Try to optimize the expression.
      Overrides:
      optimize in class AbstractAggregate
      Parameters:
      session - the session
      Returns:
      the optimized expression

    • setEvaluatable

      public void setEvaluatable(TableFilter tableFilter, boolean b)
      Description copied from class: Expression
      Tell the expression columns whether the table filter can return values now. This is used when optimizing the query.
      Overrides:
      setEvaluatable in class AbstractAggregate
      Parameters:
      tableFilter - the table filter
      b - true if the table filter can return value

    • getUnenclosedSQL

      public StringBuilder getUnenclosedSQL(StringBuilder builder, int sqlFlags)
      Description copied from class: Expression
      Get the SQL statement of this expression. This may not always be the original SQL statement, especially after optimization. Enclosing '(' and ')' are never appended.
      Specified by:
      getUnenclosedSQL in class Expression
      Parameters:
      builder - string builder
      sqlFlags - formatting flags
      Returns:
      the specified string builder

    • isEverything

      public boolean isEverything(ExpressionVisitor visitor)
      Description copied from class: Expression
      Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.
      Overrides:
      isEverything in class DataAnalysisOperation
      Parameters:
      visitor - the visitor
      Returns:
      if the criteria can be fulfilled

    • getCost

      public int getCost()
      Description copied from class: Expression
      Estimate the cost to process the expression. Used when optimizing the query, to calculate the query plan with the lowest estimated cost.
      Specified by:
      getCost in class Expression
      Returns:
      the estimated cost

    • getSelect

      public Select getSelect()
      Returns the select statement.
      Returns:
      the select statement

    • isDistinct

      public boolean isDistinct()
      Returns if distinct is used.
      Returns:
      if distinct is used