本文整理了Java中com.facebook.presto.sql.QueryUtil.aliasedNullToEmpty方法的一些代码示例，展示了QueryUtil.aliasedNullToEmpty的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。QueryUtil.aliasedNullToEmpty方法的具体详情如下：
包路径：com.facebook.presto.sql.QueryUtil
类名称：QueryUtil
方法名：aliasedNullToEmpty

QueryUtil.aliasedNullToEmpty介绍

暂无

代码示例

代码示例来源：origin: prestodb/presto

@Override
protected Node visitShowColumns(ShowColumns showColumns, Void context)
{
  QualifiedObjectName tableName = createQualifiedObjectName(session, showColumns, showColumns.getTable());
  if (!metadata.getView(session, tableName).isPresent() &&
      !metadata.getTableHandle(session, tableName).isPresent()) {
    throw new SemanticException(MISSING_TABLE, showColumns, "Table '%s' does not exist", tableName);
  }
  return simpleQuery(
      selectList(
          aliasedName("column_name", "Column"),
          aliasedName("data_type", "Type"),
          aliasedNullToEmpty("extra_info", "Extra"),
          aliasedNullToEmpty("comment", "Comment")),
      from(tableName.getCatalogName(), TABLE_COLUMNS),
      logicalAnd(
          equal(identifier("table_schema"), new StringLiteral(tableName.getSchemaName())),
          equal(identifier("table_name"), new StringLiteral(tableName.getObjectName()))),
      ordering(ascending("ordinal_position")));
}

代码示例来源：origin: uk.co.nichesolutions.presto/presto-main

@Override
protected RelationType visitShowColumns(ShowColumns showColumns, AnalysisContext context)
{
  QualifiedObjectName tableName = createQualifiedObjectName(session, showColumns, showColumns.getTable());
  if (!metadata.getView(session, tableName).isPresent() &&
      !metadata.getTableHandle(session, tableName).isPresent()) {
    throw new SemanticException(MISSING_TABLE, showColumns, "Table '%s' does not exist", tableName);
  }
  Query query = simpleQuery(
      selectList(
          aliasedName("column_name", "Column"),
          aliasedName("data_type", "Type"),
          aliasedNullToEmpty("comment", "Comment")),
      from(tableName.getCatalogName(), TABLE_COLUMNS),
      logicalAnd(
          equal(nameReference("table_schema"), new StringLiteral(tableName.getSchemaName())),
          equal(nameReference("table_name"), new StringLiteral(tableName.getObjectName()))),
      ordering(ascending("ordinal_position")));
  return process(query, context);
}