SelectUnion (H2 Database Engine wt-1.0.1 API)

java.lang.Object
- org.h2.command.Prepared
- - org.h2.command.dml.Query
  - - org.h2.command.dml.SelectUnion

```
public class SelectUnion
extends Query
```
Represents a union SELECT statement.

字段概要

字段
限定符和类型	字段和说明
`static int`	`EXCEPT` The type of an EXCEPT statement.
`static int`	`INTERSECT` The type of an INTERSECT statement.
`static int`	`UNION` The type of a UNION statement.
`static int`	`UNION_ALL` The type of a UNION ALL statement.

从类继承的字段 org.h2.command.dml.Query
distinct, limitExpr, offsetExpr, randomAccessResult, sampleSizeExpr

从类继承的字段 org.h2.command.Prepared
create, parameters, prepareAlways, session, sqlStatement

构造器概要

构造器
构造器和说明

SelectUnion(Session session, Query query)

构造器
构造器和说明
`SelectUnion(Session session, Query query)`

方法概要

所有方法实例方法具体方法
限定符和类型	方法和说明
`void`	`addGlobalCondition(Parameter param, int columnId, int comparisonType)` Add a condition to the query.
`boolean`	`allowGlobalConditions()` Check whether adding condition to the query is allowed.
`void`	`fireBeforeSelectTriggers()` Call the before triggers on all tables.
`int`	`getColumnCount()` Get the column count of this query.
`double`	`getCost()` Calculate the cost to execute this query.
`LocalResult`	`getEmptyResult()`
`ArrayList<Expression>`	`getExpressions()` The the list of select expressions.
`Query`	`getLeft()`
`String`	`getPlanSQL()` Get the SQL statement with the execution plan.
`Query`	`getRight()`
`HashSet<Table>`	`getTables()` Get all tables that are involved in this query.
`int`	`getType()` Get the command type as defined in CommandInterface
`int`	`getUnionType()`
`boolean`	`hasOrder()` Whether the query has an order.
`void`	`init()` Initialize the query.
`boolean`	`isEverything(ExpressionVisitor visitor)` Check if this expression and all sub-expressions can fulfill a criteria.
`boolean`	`isReadOnly()` Check if this command is read only.
`boolean`	`isUnion()` Check if this is a UNION query.
`void`	`mapColumns(ColumnResolver resolver, int level)` Map the columns to the given column resolver.
`void`	`prepare()` Prepare this statement.
`void`	`prepareJoinBatch()` Prepare join batching.
`LocalResult`	`query(int limit, ResultTarget target)` Execute the query, writing the result to the target result.
`ResultInterface`	`queryMeta()` Get an empty result set containing the meta data.
`protected LocalResult`	`queryWithoutCache(int maxRows, ResultTarget target)` Execute the query without checking the cache.
`void`	`setEvaluatable(TableFilter tableFilter, boolean b)` Change the evaluatable flag.
`void`	`setForUpdate(boolean forUpdate)` Set the 'for update' flag.
`void`	`setOrder(ArrayList<SelectOrderBy> order)` Set the order by list.
`void`	`setRight(Query select)`
`void`	`setSQL(String sql)` Set the SQL statement.
`void`	`setUnionType(int type)`
`void`	`updateAggregate(Session s)` Update all aggregate function values.

从类继承的方法 org.h2.command.dml.Query
disableCache, getCostAsExpression, getLimit, getMaxDataModificationId, getOffset, getParameterValues, isDistinct, isQuery, isTransactional, prepareOrder, query, setDistinct, setLimit, setOffset, setRandomAccessResult, setSampleSize

从类继承的方法 org.h2.command.Prepared
checkCanceled, checkParameters, getCurrentObjectId, getCurrentRowNumber, getObjectId, getParameters, getSQL, getSQL, getSQL, isCacheable, needRecompile, setCommand, setCurrentRowNumber, setObjectId, setParameterList, setPrepareAlways, setRow, setSession, toString, update

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

- 字段详细资料
  - UNION
```
public static final int UNION
```
    The type of a UNION statement.
    
    另请参阅:
    
    常量字段值
  - UNION_ALL
```
public static final int UNION_ALL
```
    The type of a UNION ALL statement.
    
    另请参阅:
    
    常量字段值
  - EXCEPT
```
public static final int EXCEPT
```
    The type of an EXCEPT statement.
    
    另请参阅:
    
    常量字段值
  - INTERSECT
```
public static final int INTERSECT
```
    The type of an INTERSECT statement.
    
    另请参阅:
    
    常量字段值
- 构造器详细资料
  - SelectUnion
```
public SelectUnion(Session session,
                   Query query)
```
- 方法详细资料
  - isUnion
```
public boolean isUnion()
```
    从类复制的说明: Query
    
    Check if this is a UNION query.
    
    指定者:
    
    isUnion 在类中 Query
    
    返回:
    
    true if this is a UNION query
  - prepareJoinBatch
```
public void prepareJoinBatch()
```
    从类复制的说明: Query
    
    Prepare join batching.
    
    指定者:
    
    prepareJoinBatch 在类中 Query
  - setUnionType
```
public void setUnionType(int type)
```
  - getUnionType
```
public int getUnionType()
```
  - setRight
```
public void setRight(Query select)
```
  - getLeft
```
public Query getLeft()
```
  - getRight
```
public Query getRight()
```
  - setSQL
```
public void setSQL(String sql)
```
    从类复制的说明: Prepared
    
    Set the SQL statement.
    
    覆盖:
    
    setSQL 在类中 Prepared
    
    参数:
    
    sql - the SQL statement
  - setOrder
```
public void setOrder(ArrayList<SelectOrderBy> order)
```
    从类复制的说明: Query
    
    Set the order by list.
    
    指定者:
    
    setOrder 在类中 Query
    
    参数:
    
    order - the order by list
  - hasOrder
```
public boolean hasOrder()
```
    从类复制的说明: Query
    
    Whether the query has an order.
    
    指定者:
    
    hasOrder 在类中 Query
    
    返回:
    
    true if it has
  - queryMeta
```
public ResultInterface queryMeta()
```
    从类复制的说明: Prepared
    
    Get an empty result set containing the meta data.
    
    指定者:
    
    queryMeta 在类中 Prepared
    
    返回:
    
    the result set
  - getEmptyResult
```
public LocalResult getEmptyResult()
```
  - queryWithoutCache
```
protected LocalResult queryWithoutCache(int maxRows,
                                        ResultTarget target)
```
    从类复制的说明: Query
    
    Execute the query without checking the cache. If a target is specified, the results are written to it, and the method returns null. If no target is specified, a new LocalResult is created and returned.
    
    指定者:
    
    queryWithoutCache 在类中 Query
    
    参数:
    
    maxRows - the limit as specified in the JDBC method call
    
    target - the target to write results to
    
    返回:
    
    the result
  - init
```
public void init()
```
    从类复制的说明: Query
    
    Initialize the query.
    
    指定者:
    
    init 在类中 Query
  - prepare
```
public void prepare()
```
    从类复制的说明: Prepared
    
    Prepare this statement.
    
    覆盖:
    
    prepare 在类中 Prepared
  - getCost
```
public double getCost()
```
    从类复制的说明: Query
    
    Calculate the cost to execute this query.
    
    指定者:
    
    getCost 在类中 Query
    
    返回:
    
    the cost
  - getTables
```
public HashSet<Table> getTables()
```
    从类复制的说明: Query
    
    Get all tables that are involved in this query.
    
    指定者:
    
    getTables 在类中 Query
    
    返回:
    
    the set of tables
  - getExpressions
```
public ArrayList<Expression> getExpressions()
```
    从类复制的说明: Query
    
    The the list of select expressions. This may include invisible expressions such as order by expressions.
    
    指定者:
    
    getExpressions 在类中 Query
    
    返回:
    
    the list of expressions
  - setForUpdate
```
public void setForUpdate(boolean forUpdate)
```
    从类复制的说明: Query
    
    Set the 'for update' flag.
    
    指定者:
    
    setForUpdate 在类中 Query
    
    参数:
    
    forUpdate - the new setting
  - getColumnCount
```
public int getColumnCount()
```
    从类复制的说明: Query
    
    Get the column count of this query.
    
    指定者:
    
    getColumnCount 在类中 Query
    
    返回:
    
    the column count
  - mapColumns
```
public void mapColumns(ColumnResolver resolver,
                       int level)
```
    从类复制的说明: Query
    
    Map the columns to the given column resolver.
    
    指定者:
    
    mapColumns 在类中 Query
    
    参数:
    
    resolver - the resolver
    
    level - the subquery level (0 is the top level query, 1 is the first subquery level)
  - setEvaluatable
```
public void setEvaluatable(TableFilter tableFilter,
                           boolean b)
```
    从类复制的说明: Query
    
    Change the evaluatable flag. This is used when building the execution plan.
    
    指定者:
    
    setEvaluatable 在类中 Query
    
    参数:
    
    tableFilter - the table filter
    
    b - the new value
  - addGlobalCondition
```
public void addGlobalCondition(Parameter param,
                               int columnId,
                               int comparisonType)
```
    从类复制的说明: Query
    
    Add a condition to the query. This is used for views.
    
    指定者:
    
    addGlobalCondition 在类中 Query
    
    参数:
    
    param - the parameter
    
    columnId - the column index (0 meaning the first column)
    
    comparisonType - the comparison type
  - getPlanSQL
```
public String getPlanSQL()
```
    从类复制的说明: Prepared
    
    Get the SQL statement with the execution plan.
    
    覆盖:
    
    getPlanSQL 在类中 Prepared
    
    返回:
    
    the execution plan
  - query
```
public LocalResult query(int limit,
                         ResultTarget target)
```
    从类复制的说明: Query
    
    Execute the query, writing the result to the target result.
    
    参数:
    
    limit - the maximum number of rows to return
    
    target - the target result (null will return the result)
    
    返回:
    
    the result set (if the target is not set).
  - isEverything
```
public boolean isEverything(ExpressionVisitor visitor)
```
    从类复制的说明: Query
    
    Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.
    
    指定者:
    
    isEverything 在类中 Query
    
    参数:
    
    visitor - the visitor
    
    返回:
    
    if the criteria can be fulfilled
  - isReadOnly
```
public boolean isReadOnly()
```
    从类复制的说明: Prepared
    
    Check if this command is read only.
    
    覆盖:
    
    isReadOnly 在类中 Prepared
    
    返回:
    
    true if it is
  - updateAggregate
```
public void updateAggregate(Session s)
```
    从类复制的说明: Query
    
    Update all aggregate function values.
    
    指定者:
    
    updateAggregate 在类中 Query
    
    参数:
    
    s - the session
  - fireBeforeSelectTriggers
```
public void fireBeforeSelectTriggers()
```
    从类复制的说明: Query
    
    Call the before triggers on all tables.
    
    指定者:
    
    fireBeforeSelectTriggers 在类中 Query
  - getType
```
public int getType()
```
    从类复制的说明: Prepared
    
    Get the command type as defined in CommandInterface
    
    指定者:
    
    getType 在类中 Prepared
    
    返回:
    
    the statement type
  - allowGlobalConditions
```
public boolean allowGlobalConditions()
```
    从类复制的说明: Query
    
    Check whether adding condition to the query is allowed. This is not allowed for views that have an order by and a limit, as it would affect the returned results.
    
    指定者:
    
    allowGlobalConditions 在类中 Query
    
    返回:
    
    true if adding global conditions is allowed

类 SelectUnion

字段概要

从类继承的字段 org.h2.command.dml.Query

从类继承的字段 org.h2.command.Prepared

构造器概要

方法概要

从类继承的方法 org.h2.command.dml.Query

从类继承的方法 org.h2.command.Prepared

从类继承的方法 java.lang.Object

字段详细资料

UNION

UNION_ALL

EXCEPT

INTERSECT

构造器详细资料

SelectUnion

方法详细资料

isUnion

prepareJoinBatch

setUnionType

getUnionType

setRight

getLeft

getRight

setSQL

setOrder

hasOrder

queryMeta

getEmptyResult

queryWithoutCache

init

prepare

getCost

getTables

getExpressions

setForUpdate

getColumnCount

mapColumns

setEvaluatable

addGlobalCondition

getPlanSQL

query

isEverything

isReadOnly

updateAggregate

fireBeforeSelectTriggers

getType

allowGlobalConditions