Merge pull request #21144 from taosdata/feat/TD-19801

feat(query): support interp with super table

docs/en/12-taos-sql/06-select.md

@@ -55,7 +55,7 @@ window_clause: {
   | INTERVAL(interval_val [, interval_offset]) [SLIDING (sliding_val)] [WATERMARK(watermark_val)] [FILL(fill_mod_and_val)]
 
 interp_clause:
-    RANGE(ts_val, ts_val), EVERY(every_val), FILL(fill_mod_and_val)
+    RANGE(ts_val, ts_val) EVERY(every_val) FILL(fill_mod_and_val)
 
 partition_by_clause:
     PARTITION BY expr [, expr] ...

docs/en/12-taos-sql/10-function.md

@@ -886,7 +886,7 @@ INTERP(expr)
 - The output time range of `INTERP` is specified by `RANGE(timestamp1,timestamp2)` parameter, with timestamp1 <= timestamp2. timestamp1 is the starting point of the output time range and must be specified. timestamp2 is the ending point of the output time range and must be specified.
 - The number of rows in the result set of `INTERP` is determined by the parameter `EVERY(time_unit)`. Starting from timestamp1, one interpolation is performed for every time interval specified `time_unit` parameter. The parameter `time_unit` must be an integer, with no quotes, with a time unit of: a(millisecond)), s(second), m(minute), h(hour), d(day), or w(week). For example, `EVERY(500a)` will interpolate every 500 milliseconds.
 - Interpolation is performed based on `FILL` parameter. For more information about FILL clause, see [FILL Clause](../distinguished/#fill-clause).
-- `INTERP` can only be used to interpolate in single timeline. So it must be used with `partition by tbname` when it's used on a STable.
+- `INTERP` can be applied to supertable by interpolating primary key sorted data of all its childtables. It can also be used with `partition by tbname` when applied to supertable to generate interpolation on each single timeline.
 - Pseudocolumn `_irowts` can be used along with `INTERP` to return the timestamps associated with interpolation points(support after version 3.0.2.0).
 - Pseudocolumn `_isfilled` can be used along with `INTERP` to indicate whether the results are original records or data points generated by interpolation algorithm(support after version 3.0.3.0).
 

docs/zh/12-taos-sql/06-select.md

@@ -55,7 +55,7 @@ window_clause: {
   | INTERVAL(interval_val [, interval_offset]) [SLIDING (sliding_val)] [WATERMARK(watermark_val)] [FILL(fill_mod_and_val)]
 
 interp_clause:
-    RANGE(ts_val, ts_val), EVERY(every_val), FILL(fill_mod_and_val)
+    RANGE(ts_val, ts_val) EVERY(every_val) FILL(fill_mod_and_val)
 
 partition_by_clause:
     PARTITION BY expr [, expr] ...

docs/zh/12-taos-sql/10-function.md

@@ -888,7 +888,7 @@ INTERP(expr)
 - INTERP 的输出时间范围根据 RANGE(timestamp1,timestamp2)字段来指定，需满足 timestamp1 <= timestamp2。其中 timestamp1（必选值）为输出时间范围的起始值，即如果 timestamp1 时刻符合插值条件则 timestamp1 为输出的第一条记录，timestamp2（必选值）为输出时间范围的结束值，即输出的最后一条记录的 timestamp 不能大于 timestamp2。
 - INTERP 根据 EVERY(time_unit) 字段来确定输出时间范围内的结果条数，即从 timestamp1 开始每隔固定长度的时间（time_unit 值）进行插值，time_unit 可取值时间单位：1a(毫秒)，1s(秒)，1m(分)，1h(小时)，1d(天)，1w(周)。例如 EVERY(500a) 将对于指定数据每500毫秒间隔进行一次插值.
 - INTERP 根据 FILL 字段来决定在每个符合输出条件的时刻如何进行插值。关于 FILL 子句如何使用请参考 [FILL 子句](../distinguished/#fill-子句)
-- INTERP 只能在一个时间序列内进行插值，因此当作用于超级表时必须跟 partition by tbname 一起使用。
+- INTERP 作用于超级表时, 会将该超级表下的所有子表数据按照主键列排序后进行插值计算，也可以搭配 PARTITION BY tbname 使用，将结果强制规约到单个时间线。
 - INTERP 可以与伪列 _irowts 一起使用，返回插值点所对应的时间戳(3.0.2.0版本以后支持)。
 - INTERP 可以与伪列 _isfilled 一起使用，显示返回结果是否为原始记录或插值算法产生的数据(3.0.3.0版本以后支持)。
 

source/libs/parser/src/parTranslater.c

@@ -1518,9 +1518,7 @@ static int32_t translateInterpFunc(STranslateContext* pCxt, SFunctionNode* pFunc
   SSelectStmt* pSelect = (SSelectStmt*)pCxt->pCurrStmt;
   SNode*       pTable = pSelect->pFromTable;
 
-  if ((NULL != pTable && (QUERY_NODE_REAL_TABLE != nodeType(pTable) ||
-                          (TSDB_CHILD_TABLE != ((SRealTableNode*)pTable)->pMeta->tableType &&
-                           TSDB_NORMAL_TABLE != ((SRealTableNode*)pTable)->pMeta->tableType)))) {
+  if ((NULL != pTable && QUERY_NODE_REAL_TABLE != nodeType(pTable))) {
     return generateSyntaxErrMsgExt(&pCxt->msgBuf, TSDB_CODE_PAR_ONLY_SUPPORT_SINGLE_TABLE,
                                    "%s is only supported in single table query", pFunc->functionName);
   }