com.alibaba.druid.sql.ast.statement.SQLSelectItem Java Examples

private static boolean isSupportSelect(String stmt) {
    SQLStatementParser parser = new MySqlStatementParser(stmt);
    SQLStatement statement = parser.parseStatement();
    if (!(statement instanceof SQLSelectStatement)) {
        return false;
    }

    SQLSelectQuery sqlSelectQuery = ((SQLSelectStatement) statement).getSelect().getQuery();
    if (!(sqlSelectQuery instanceof MySqlSelectQueryBlock)) {
        return false;
    }
    MySqlSelectQueryBlock selectQueryBlock = (MySqlSelectQueryBlock) sqlSelectQuery;
    SQLTableSource mysqlFrom = selectQueryBlock.getFrom();
    if (mysqlFrom != null) {
        return false;
    }
    for (SQLSelectItem item : selectQueryBlock.getSelectList()) {
        SQLExpr selectItem = item.getExpr();
        if (!isVariantRef(selectItem)) {
            return false;
        }
    }
    return true;
}
 

private boolean visitSelectItems(List<SQLSelectItem> selectItems, boolean distinct) {
	boolean rewriteDistinct = false;
	if (this.subSelect) {
		// sub select
		print0(ucase ? "SELECT " : "select ");
		if (distinct) {
			print0(ucase ? "DISTINCT " : "distinct ");
		}
		printSelectItems(selectItems);
	} else {
		if (distinct) {
			// select distinct a,b,... from xxx
			print0(ucase ? "SELECT COUNT(*) FROM (SELECT DISTINCT " : "select count(*) from (select distinct ");
			printSelectItems(selectItems);
			rewriteDistinct = true;
		} else {
			// normal select
			print0(ucase ? "SELECT COUNT(*) " : "select count(*) ");
		}
	}
	this.subSelect = true;
	return rewriteDistinct;
}
 

@Override
public void parseFrom(SQLSelectQueryBlock queryBlock) {
    if (lexer.token() != Token.FROM) {
        return;
    }

    lexer.nextTokenIdent();

    if (lexer.token() == Token.UPDATE) { // taobao returning to urgly syntax
        updateStmt = this.parseUpdateStatment();
        List<SQLExpr> returnning = updateStmt.getReturning();
        for (SQLSelectItem item : queryBlock.getSelectList()) {
            SQLExpr itemExpr = item.getExpr();
            itemExpr.setParent(updateStmt);
            returnning.add(itemExpr);
        }
        returningFlag = true;
        return;
    }

    queryBlock.setFrom(parseTableSource());
}
 

private String getFieldName(SQLSelectItem item){
	if (item.getExpr() instanceof SQLPropertyExpr) {			
		return item.getExpr().toString();//字段别名
	}
	else {
		return item.toString();
	}
}
 

private String getMethodInvokeFieldName(SQLSelectItem item){
	SQLMethodInvokeExpr invoke = (SQLMethodInvokeExpr)item.getExpr();
	List<SQLExpr> itemExprs = invoke.getParameters();
	for(SQLExpr itemExpr:itemExprs){
		if (itemExpr instanceof SQLPropertyExpr) {
			return itemExpr.toString();//字段别名
		}
	}
	return item.toString();
}
 

private void parserFields(List<SQLSelectItem> mysqlSelectList){
		//显示的字段
		String key="";
		String value ="";
		String exprfield = "";
		for(SQLSelectItem item : mysqlSelectList) {
			if (item.getExpr() instanceof SQLAllColumnExpr) {
				//*解析
				setField(item.toString(), item.toString());
			}
			else {
				if (item.getExpr() instanceof SQLAggregateExpr) {
					SQLAggregateExpr expr =(SQLAggregateExpr)item.getExpr();
					 key = getExprFieldName(expr);
					 setField(key, value);
				}else if(item.getExpr() instanceof SQLMethodInvokeExpr){
					key = getMethodInvokeFieldName(item);
					exprfield=getFieldName(item);
//					value=item.getAlias();
					setField(key, value,exprfield);
				}else {					
					key=getFieldName(item);
					value=item.getAlias();
					setField(key, value);
				}			
				
			}
		}			
	}
 

private static FieldPacket[] generateFieldPacket(List<SQLSelectItem> selectList) {
    FieldPacket[] fields = new FieldPacket[selectList.size()];
    for (int i = 0; i < selectList.size(); i++) {
        String columnName;
        SQLSelectItem selectItem = selectList.get(i);
        if (selectItem.getAlias() != null) {
            columnName = StringUtil.removeBackQuote(selectList.get(i).getAlias());
        } else {
            columnName = StringUtil.removeBackQuote(selectItem.toString());
        }
        fields[i] = PacketUtil.getField(columnName, Fields.FIELD_TYPE_VAR_STRING);
    }
    return fields;
}
 

protected String getFieldName(SQLSelectItem item){
    if ((item.getExpr() instanceof SQLPropertyExpr)||(item.getExpr() instanceof SQLMethodInvokeExpr)
            || (item.getExpr() instanceof SQLIdentifierExpr) || item.getExpr() instanceof SQLBinaryOpExpr) {
        return item.getExpr().toString();//字段别名
    }else {
        return item.toString();
    }
}
 

/**
 * 解析Orderby
 * @param result
 * @param plan
 * @param mysqlSelectQuery
 */
protected void parseOrderby(ParseResult result, ExecutePlan plan, MySqlSelectQueryBlock mysqlSelectQuery){
    if (mysqlSelectQuery.getOrderBy() == null){
        return;
    }
    List<SQLSelectOrderByItem> orderByItems = mysqlSelectQuery.getOrderBy().getItems();
    if (orderByItems == null || orderByItems.size() == 0){
        return;
    }
    List<SQLSelectItem> selectList      = mysqlSelectQuery.getSelectList();
    List<OrderbyColumn> orderbyColumns  = new ArrayList<OrderbyColumn>(orderByItems.size());
    for(SQLSelectOrderByItem item : orderByItems){
        String name = StringUtil.removeDot(item.getExpr().toString());
        if (result.getAliaColumns() != null){
            String alias = result.getAliaColumns().get(name);
            if (alias != null){
                // select user_id as uid ....order by user_id
                // 要把oderby的user_id转换为uid,以便结果集合并
                orderbyColumns.add(new OrderbyColumn(alias, OrderbyColumn.buildOrderbyType(item.getType())));
                continue;
            }
        }
        if (!result.isHasAllColumnExpr()){
            // select列表中没有orderby的字段 添加，用于后面做合并
            SQLIdentifierExpr exp = new SQLIdentifierExpr(name);

            // item
            SQLSelectItem addItem = new SQLSelectItem();
            addItem.setExpr(exp);
            exp.setParent(item);
            selectList.add(addItem);
        }
        orderbyColumns.add(new OrderbyColumn(name, OrderbyColumn.buildOrderbyType(item.getType())));
    }
    plan.setOrderbyColumns(orderbyColumns);
}
 

private void printSelectItems(List<SQLSelectItem> selectItems) {
	for (int i = 0; i < selectItems.size(); ++i) {
		SQLSelectItem item = selectItems.get(i);
		if (i > 0) {
			print0(",");
		}
		item.accept(this);
	}
}
 

private void findSelect(MySqlSelectQueryBlock query, Select select, String tableAlias) throws SqlParseException {
    List<SQLSelectItem> selectList = query.getSelectList();
    for (SQLSelectItem sqlSelectItem : selectList) {
        Field field = FieldMaker.makeField(sqlSelectItem.getExpr(), sqlSelectItem.getAlias(), tableAlias);
        select.addField(field);
    }
}
 

@Override
public SQLSelectItem parseSelectItem()
{
    parseTop();
    return super.parseSelectItem();
}
 

/**
 * 解析聚合函数
 * @param result
 * @param plan
 * @param mysqlSelectQuery
 */
protected void parseAggregate(ParseResult result, ExecutePlan plan, MySqlSelectQueryBlock mysqlSelectQuery){
    // 要合并的列
    Map<String, MergeColumn.MergeType>      aggrColumns         = new HashMap<String, MergeColumn.MergeType>();
    Map<String/*field*/, String/*alias*/>   aliaColumns         = new HashMap<String, String>();
    // 查询的列
    List<SQLSelectItem>                     selectList          = mysqlSelectQuery.getSelectList();
    int                                     size                = selectList.size();
    //boolean                               isDistinct          = mysqlSelectQuery.getDistionOption() == 2;
    List<String>                            avgColumns          = null;

    for (int i = 0; i < size; i++){
        SQLSelectItem item = selectList.get(i);
        if (item.getExpr() instanceof SQLAggregateExpr) {
            SQLAggregateExpr expr = (SQLAggregateExpr) item.getExpr();
            String method = expr.getMethodName();
            // 只处理有别名的情况，无别名添加别名，否则某些数据库会得不到正确结果处理
            MergeColumn.MergeType mergeType = MergeColumn.buildMergeType(method);

            if (MergeColumn.MergeType.MERGE_UNSUPPORT == mergeType) {
                continue;
            }

            // 没有别名的 增加别名
            if (item.getAlias() == null || item.getAlias().length() <= 0) {
                item.setAlias(method + i);
            }

            // 保存合并列
            aggrColumns.put(item.getAlias(), mergeType);

            if (MergeColumn.MergeType.MERGE_AVG == mergeType) {
                if (avgColumns == null) {
                    avgColumns = new ArrayList<String>();
                }
                avgColumns.add(item.getAlias());

                //sum
                // 表达式
                SQLAggregateExpr sumExp = new SQLAggregateExpr("SUM");
                ReflectionUtils.copyProperties(expr, sumExp);
                sumExp.getArguments().addAll(expr.getArguments());
                sumExp.setMethodName("SUM");

                // item
                SQLSelectItem sum = new SQLSelectItem();
                String sumColName = item.getAlias() + "SUM";
                sum.setAlias(sumColName);
                sum.setExpr(sumExp);

                // 替换
                selectList.add(sum);
                aggrColumns.put(sumColName, MergeColumn.MergeType.MERGE_SUM);

                // count
                // 表达式
                SQLAggregateExpr countExp = new SQLAggregateExpr("COUNT");
                ReflectionUtils.copyProperties(expr, countExp);
                countExp.getArguments().addAll(expr.getArguments());
                countExp.setMethodName("COUNT");

                // item
                SQLSelectItem count = new SQLSelectItem();
                String countColName = item.getAlias() + "COUNT";
                count.setAlias(countColName);
                count.setExpr(countExp);

                // 替换
                selectList.add(count);
                aggrColumns.put(countColName, MergeColumn.MergeType.MERGE_COUNT);

                // 原始avg
                aggrColumns.put(item.getAlias(), MergeColumn.MergeType.MERGE_AVG);
            }
        }else
        // 所有select字段的别名
        if (item.getExpr() instanceof SQLAllColumnExpr){
            // select *
            result.setHasAllColumnExpr(true);
        }else if(item.getExpr() instanceof SQLIdentifierExpr){
            // 只有普通select list的字段才放到别名列表中，用于orderby groupby的取值比较
            String alia = item.getAlias();
            //String field = getFieldName(item);
            String field = item.getExpr().toString();
            alia = alia == null ? field : alia;
            aliaColumns.put(field, alia);
        }
    }
    plan.setMergeColumns(aggrColumns);
    result.setAliaColumns(aliaColumns);
}
 

/**
 * 解析groupby
 * @param result
 * @param plan
 * @param mysqlSelectQuery
 */
protected void parseGroupBy(ParseResult result, ExecutePlan plan, MySqlSelectQueryBlock mysqlSelectQuery){
    if(mysqlSelectQuery.getGroupBy() == null) {
        return;
    }
    List<SQLExpr> groupByItems = mysqlSelectQuery.getGroupBy().getItems();
    if (groupByItems == null || groupByItems.size() == 0){
        return;
    }
    List<SQLSelectItem> selectList      = mysqlSelectQuery.getSelectList();
    List<String> groupbyColumns  = new ArrayList<String>(groupByItems.size());
    for(SQLExpr item : groupByItems){
        String name = null;
        if (item instanceof MySqlSelectGroupByExpr){
            name = StringUtil.removeDot(((MySqlSelectGroupByExpr) item).getExpr().toString());
        }else if (item instanceof SQLIdentifierExpr){
            name = item.toString();
        }else if (item instanceof SQLName){
            name = ((SQLName) item).getSimpleName();
        }else {
            throw new BayMaxException("group by 不支持的表达式:" + item.toString());
        }
        if (result.getAliaColumns() != null){
            // 有别名,说明在select list中使用了别名
            String alias = result.getAliaColumns().get(name);
            if (alias != null){
                // select user_id as uid ....order by user_id
                // 要把oderby的user_id转换为uid,以便结果集合并,这个替换是等价的
                // 因为合并的时候需要根据orderby的字段,取值,比较
                groupbyColumns.add(alias);
                continue;
            }
        }
        if (!result.isHasAllColumnExpr()){
            // select列表中没有orderby的字段 添加，用于后面做合并
            SQLIdentifierExpr exp = new SQLIdentifierExpr(name);
            // item
            SQLSelectItem addItem = new SQLSelectItem();
            addItem.setExpr(exp);
            exp.setParent(item);
            selectList.add(addItem);
        }
        groupbyColumns.add(name);
    }
    plan.setGroupbyColumns(groupbyColumns);
}
 

private void initConditionExpr() {
	SQLBinaryOperator startOperator, endOperator;
	// 上下线每个条件的边际表达式
	SQLBinaryOpExpr startBoundaryExpr = null, endBoundaryExpr = null;

	for (SQLSelectOrderByItem orderByEle : context.getOrderBy().getItems()) {
		if (orderByEle.getType() == null || ((SQLOrderingSpecification) orderByEle.getType()).name().equals("ASC")) {
			startOperator = SQLBinaryOperator.GreaterThan;
			endOperator = SQLBinaryOperator.LessThan;
		} else {
			startOperator = SQLBinaryOperator.LessThan;
			endOperator = SQLBinaryOperator.GreaterThan;
		}
		try {
			SQLExpr starColumnExpr = convertColumnDataToSQLExpr(startData.get(orderByEle.getExpr().toString()));
			SQLExpr endColumnExpr = convertColumnDataToSQLExpr(endData.get(orderByEle.getExpr().toString()));
			SQLExpr compareExpr = orderByEle.getExpr();
			// 如果orderby的column是一个表达式的结果，则把表达式作为新条件的比较变量
			SQLObjectImpl selectItem = context.getSelectItemMap().get(orderByEle.getExpr().toString());
			if (selectItem == null) {
				selectItem = context.getSelectItemMap().get(orderByEle.getExpr().toString().toLowerCase());

				if (selectItem == null) {
					selectItem = context.getSelectItemMap().get(orderByEle.getExpr().toString().toUpperCase());
				}
			}

			if (selectItem != null) {
				if (selectItem instanceof SQLSelectItem) {
					compareExpr = ((SQLSelectItem) selectItem).getExpr();
				}
			}

			SQLBinaryOpExpr startExpr = new SQLBinaryOpExpr(compareExpr, startOperator, starColumnExpr);
			SQLBinaryOpExpr endExpr = new SQLBinaryOpExpr(compareExpr, endOperator, endColumnExpr);

			if (startBoundaryExpr != null) {
				// 在上一个边际表达式的基础上加上and条件
				addStartConditionExpr(new SQLBinaryOpExpr(startBoundaryExpr, SQLBinaryOperator.BooleanAnd, startExpr));
				addEndConditionExpr(new SQLBinaryOpExpr(endBoundaryExpr, SQLBinaryOperator.BooleanAnd, endExpr));
				startBoundaryExpr = new SQLBinaryOpExpr(startBoundaryExpr, SQLBinaryOperator.BooleanAnd,
				      new SQLBinaryOpExpr(compareExpr, SQLBinaryOperator.Equality, starColumnExpr));
				endBoundaryExpr = new SQLBinaryOpExpr(endBoundaryExpr, SQLBinaryOperator.BooleanAnd,
				      new SQLBinaryOpExpr(compareExpr, SQLBinaryOperator.Equality, endColumnExpr));
			} else {
				addStartConditionExpr(startExpr);
				addEndConditionExpr(endExpr);
				startBoundaryExpr = new SQLBinaryOpExpr(compareExpr, SQLBinaryOperator.Equality, starColumnExpr);
				endBoundaryExpr = new SQLBinaryOpExpr(compareExpr, SQLBinaryOperator.Equality, endColumnExpr);
			}
		} catch (SQLException ignore) {
		}
	}
	// 最后补上边际条件
	addStartConditionExpr(startBoundaryExpr);
	addEndConditionExpr(endBoundaryExpr);
}
 

@Override
public boolean visit(MySqlSelectQueryBlock x) {
	result.getMergeContext().increQueryCount();
	Map<String, SQLObjectImpl> selectItemMap = result.getMergeContext().getSelectItemMap();
	Map<String, String> columnNameAliasMapping = result.getMergeContext().getColumnNameAliasMapping();

	for (SQLSelectItem column : x.getSelectList()) {
		String name = null;
		if (column.getExpr() instanceof SQLAggregateExpr) {
			SQLAggregateExpr expr = (SQLAggregateExpr) column.getExpr();
			SQLExpr argument = expr.getArguments().get(0);
			if (argument instanceof SQLAllColumnExpr) {
				name = expr.getMethodName() + "(*)";
			} else if (argument instanceof SQLIntegerExpr) {
				name = expr.getMethodName() + "(1)";
			} else {
				name = expr.getMethodName() + "(" + argument.toString() + ")";
				if (column.getAlias() != null) {
					columnNameAliasMapping.put(name, column.getAlias());
				}
			}

			result.getMergeContext().setAggregate(true);
		} else if (column.getExpr() instanceof SQLIdentifierExpr || column.getExpr() instanceof SQLPropertyExpr) {
			name = ((SQLName) column.getExpr()).getSimpleName();

			if (column.getAlias() != null) {
				SQLName identifier = (SQLName) column.getExpr();
				columnNameAliasMapping.put(identifier.getSimpleName(), column.getAlias());
			}
		} else {
			// ignore SQLAllColumnExpr,SQLMethodInvokeExpr and etc.
		}

		selectItemMap.put(column.getAlias() == null ? name : column.getAlias(), column);
	}

	if (x.getDistionOption() == 2) {
		result.getMergeContext().setDistinct(true);
	}

	return true;
}