[FLINK-21774][sql-client] Do not display column names when return set…

… is emtpy in SQL Client

flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/api/internal/TableEnvironmentImpl.java

@@ -628,18 +628,15 @@ public boolean dropTemporaryView(String path) {
 
  @Override
  public String[] listUserDefinedFunctions() {
- return sortFunctions(functionCatalog.getUserDefinedFunctions());
+ String[] functions = functionCatalog.getUserDefinedFunctions();
+ Arrays.sort(functions);
+ return functions;
  }
 
  @Override
  public String[] listFunctions() {
- return sortFunctions(functionCatalog.getFunctions());
- }
-
- private String[] sortFunctions(String[] functions) {
- if (functions != null && functions.length > 0) {
- Arrays.sort(functions);
- }
+ String[] functions = functionCatalog.getFunctions();
+ Arrays.sort(functions);
  return functions;
  }
 

flink-table/flink-table-common/src/main/java/org/apache/flink/table/utils/PrintUtils.java

@@ -116,60 +116,61 @@ public static void printAsTableauForm(
  String nullColumn,
  boolean deriveColumnWidthByType,
  boolean printRowKind) {
- if (it.hasNext()) {
- final List<TableColumn> columns = tableSchema.getTableColumns();
- String[] columnNames =
- columns.stream().map(TableColumn::getName).toArray(String[]::new);
- if (printRowKind) {
- columnNames =
- Stream.concat(Stream.of(ROW_KIND_COLUMN), Arrays.stream(columnNames))
- .toArray(String[]::new);
- }
+ if (!it.hasNext()) {
+ printWriter.println("Empty set");
+ printWriter.flush();
+ return;
+ }
+ final List<TableColumn> columns = tableSchema.getTableColumns();
+ String[] columnNames = columns.stream().map(TableColumn::getName).toArray(String[]::new);
+ if (printRowKind) {
+ columnNames =
+ Stream.concat(Stream.of(ROW_KIND_COLUMN), Arrays.stream(columnNames))
+ .toArray(String[]::new);
+ }
 
- final int[] colWidths;
- if (deriveColumnWidthByType) {
- colWidths =
- columnWidthsByType(
- columns,
- maxColumnWidth,
- nullColumn,
- printRowKind ? ROW_KIND_COLUMN : null);
- } else {
- final List<Row> rows = new ArrayList<>();
- final List<String[]> content = new ArrayList<>();
- content.add(columnNames);
- while (it.hasNext()) {
- Row row = it.next();
- rows.add(row);
- content.add(rowToString(row, nullColumn, printRowKind));
- }
- colWidths = columnWidthsByContent(columnNames, content, maxColumnWidth);
- it = rows.iterator();
+ final int[] colWidths;
+ if (deriveColumnWidthByType) {
+ colWidths =
+ columnWidthsByType(
+ columns,
+ maxColumnWidth,
+ nullColumn,
+ printRowKind ? ROW_KIND_COLUMN : null);
+ } else {
+ final List<Row> rows = new ArrayList<>();
+ final List<String[]> content = new ArrayList<>();
+ content.add(columnNames);
+ while (it.hasNext()) {
+ Row row = it.next();
+ rows.add(row);
+ content.add(rowToString(row, nullColumn, printRowKind));
  }
+ colWidths = columnWidthsByContent(columnNames, content, maxColumnWidth);
+ it = rows.iterator();
+ }
 
-  final String borderline = PrintUtils.genBorderLine(colWidths);
-  // print border line
-  printWriter.println(borderline);
-  // print field names
-  PrintUtils.printSingleRow(colWidths, columnNames, printWriter);
-  // print border line
-  printWriter.println(borderline);
+ final String borderline = PrintUtils.genBorderLine(colWidths);
+ // print border line
+ printWriter.println(borderline);
+ // print field names
+ PrintUtils.printSingleRow(colWidths, columnNames, printWriter);
+ // print border line
+ printWriter.println(borderline);
 
- long numRows = 0;
- while (it.hasNext()) {
- String[] cols = rowToString(it.next(), nullColumn, printRowKind);
- // print content
- printSingleRow(colWidths, cols, printWriter);
- numRows++;
- }
+ long numRows = 0;
+ while (it.hasNext()) {
+ String[] cols = rowToString(it.next(), nullColumn, printRowKind);
 
- // print border line
- printWriter.println(borderline);
- final String rowTerm = numRows > 1 ? "rows" : "row";
- printWriter.println(numRows + " " + rowTerm + " in set");
- } else {
- printWriter.println("Empty set");
+ // print content
+ printSingleRow(colWidths, cols, printWriter);
+ numRows++;
  }
+
+ // print border line
+ printWriter.println(borderline);
+ final String rowTerm = numRows > 1 ? "rows" : "row";
+ printWriter.println(numRows + " " + rowTerm + " in set");
  printWriter.flush();
  }