val env = StreamExecutionEnvironment.getExecutionEnvironment
val tableEnv = StreamTableEnvironment.create(env)

//  从外部数据源读取 DataStream 
val ds: DataStream[(Long, String, Integer)] = env.addSource(...)

// 使用 SQL 查询内联的（未注册的）表
val table = ds.toTable(tableEnv, $"user", $"product", $"amount")
val result = tableEnv.sqlQuery(
  s"SELECT SUM(amount) FROM $table WHERE product LIKE ‘%Rubber%‘")

// 使用名称 "Orders" 注册一个 DataStream 
tableEnv.createTemporaryView("Orders", ds, $"user", $"product", $"amount")
// 在表上执行 SQL 查询并得到以新表返回的结果
val result2 = tableEnv.sqlQuery(
  "SELECT product, amount FROM Orders WHERE product LIKE ‘%Rubber%‘")

// 创建并注册一个 TableSink
val schema = new Schema()
    .field("product", DataTypes.STRING())
    .field("amount", DataTypes.INT())

tableEnv.connect(new FileSystem().path("/path/to/file"))
    .withFormat(...)
    .withSchema(schema)
    .createTemporaryTable("RubberOrders")

// 在表上执行插入操作，并把结果发出到 TableSink
tableEnv.executeSql(
  "INSERT INTO RubberOrders SELECT product, amount FROM Orders WHERE product LIKE ‘%Rubber%‘")

val env = StreamExecutionEnvironment.getExecutionEnvironment()
val tableEnv = StreamTableEnvironment.create(env, settings)
// enable checkpointing
tableEnv.getConfig.getConfiguration.set(
  ExecutionCheckpointingOptions.CHECKPOINTING_MODE, CheckpointingMode.EXACTLY_ONCE)
tableEnv.getConfig.getConfiguration.set(
  ExecutionCheckpointingOptions.CHECKPOINTING_INTERVAL, Duration.ofSeconds(10))

tableEnv.executeSql("CREATE TABLE Orders (`user` BIGINT, product STRING, amount INT) WITH (...)")

// execute SELECT statement
val tableResult1 = tableEnv.executeSql("SELECT * FROM Orders")
val it = tableResult1.collect()
try while (it.hasNext) {
  val row = it.next
  // handle row
}
finally it.close() // close the iterator to avoid resource leak

// execute Table
val tableResult2 = tableEnv.sqlQuery("SELECT * FROM Orders").execute()
tableResult2.print()

query:
  values
  | {
      select
      | selectWithoutFrom
      | query UNION [ ALL ] query
      | query EXCEPT query
      | query INTERSECT query
    }
    [ ORDER BY orderItem [, orderItem ]* ]
    [ LIMIT { count | ALL } ]
    [ OFFSET start { ROW | ROWS } ]
    [ FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } ONLY]

orderItem:
  expression [ ASC | DESC ]

select:
  SELECT [ ALL | DISTINCT ]
  { * | projectItem [, projectItem ]* }
  FROM tableExpression
  [ WHERE booleanExpression ]
  [ GROUP BY { groupItem [, groupItem ]* } ]
  [ HAVING booleanExpression ]
  [ WINDOW windowName AS windowSpec [, windowName AS windowSpec ]* ]

selectWithoutFrom:
  SELECT [ ALL | DISTINCT ]
  { * | projectItem [, projectItem ]* }

projectItem:
  expression [ [ AS ] columnAlias ]
  | tableAlias . *

tableExpression:
  tableReference [, tableReference ]*
  | tableExpression [ NATURAL ] [ LEFT | RIGHT | FULL ] JOIN tableExpression [ joinCondition ]

joinCondition:
  ON booleanExpression
  | USING ‘(‘ column [, column ]* ‘)‘

tableReference:
  tablePrimary
  [ matchRecognize ]
  [ [ AS ] alias [ ‘(‘ columnAlias [, columnAlias ]* ‘)‘ ] ]

tablePrimary:
  [ TABLE ] [ [ catalogName . ] schemaName . ] tableName [ dynamicTableOptions ]
  | LATERAL TABLE ‘(‘ functionName ‘(‘ expression [, expression ]* ‘)‘ ‘)‘
  | UNNEST ‘(‘ expression ‘)‘

dynamicTableOptions:
  /*+ OPTIONS(key=val [, key=val]*) */

key:
  stringLiteral

val:
  stringLiteral

values:
  VALUES expression [, expression ]*

groupItem:
  expression
  | ‘(‘ ‘)‘
  | ‘(‘ expression [, expression ]* ‘)‘
  | CUBE ‘(‘ expression [, expression ]* ‘)‘
  | ROLLUP ‘(‘ expression [, expression ]* ‘)‘
  | GROUPING SETS ‘(‘ groupItem [, groupItem ]* ‘)‘

windowRef:
    windowName
  | windowSpec

windowSpec:
    [ windowName ]
    ‘(‘
    [ ORDER BY orderItem [, orderItem ]* ]
    [ PARTITION BY expression [, expression ]* ]
    [
        RANGE numericOrIntervalExpression {PRECEDING}
      | ROWS numericExpression {PRECEDING}
    ]
    ‘)‘

matchRecognize:
      MATCH_RECOGNIZE ‘(‘
      [ PARTITION BY expression [, expression ]* ]
      [ ORDER BY orderItem [, orderItem ]* ]
      [ MEASURES measureColumn [, measureColumn ]* ]
      [ ONE ROW PER MATCH ]
      [ AFTER MATCH
            ( SKIP TO NEXT ROW
            | SKIP PAST LAST ROW
            | SKIP TO FIRST variable
            | SKIP TO LAST variable
            | SKIP TO variable )
      ]
      PATTERN ‘(‘ pattern ‘)‘
      [ WITHIN intervalLiteral ]
      DEFINE variable AS condition [, variable AS condition ]*
      ‘)‘

measureColumn:
      expression AS alias

pattern:
      patternTerm [ ‘|‘ patternTerm ]*

patternTerm:
      patternFactor [ patternFactor ]*

patternFactor:
      variable [ patternQuantifier ]

patternQuantifier:
      ‘*‘
  |   ‘*?‘
  |   ‘+‘
  |   ‘+?‘
  |   ‘?‘
  |   ‘??‘
  |   ‘{‘ { [ minRepeat ], [ maxRepeat ] } ‘}‘ [‘?‘]
  |   ‘{‘ repeat ‘}‘