未验证 提交 8528abf9 编写于 作者: S Shengliang Guan 提交者: GitHub

Merge pull request #16605 from taosdata/docs/fixSelectClause

fix: fix doc select clause issue
......@@ -52,11 +52,6 @@ window_clause: {
| STATE_WINDOW(col)
| INTERVAL(interval_val [, interval_offset]) [SLIDING (sliding_val)] [WATERMARK(watermark_val)] [FILL(fill_mod_and_val)]
changes_option: {
DURATION duration_val
| ROWS rows_val
}
group_by_clause:
GROUP BY expr [, expr] ... HAVING condition
......@@ -126,7 +121,6 @@ SELECT DISTINCT col_name [, col_name ...] FROM tb_name;
1. Configuration parameter `maxNumOfDistinctRes` in `taos.cfg` is used to control the number of rows to output. The minimum configurable value is 100,000, the maximum configurable value is 100,000,000, the default value is 1,000,000. If the actual number of rows exceeds the value of this parameter, only the number of rows specified by this parameter will be output.
2. It can't be guaranteed that the results selected by using `DISTINCT` on columns of `FLOAT` or `DOUBLE` are exactly unique because of the precision errors in floating point numbers.
3. `DISTINCT` can't be used in the sub-query of a nested query statement, and can't be used together with aggregate functions, `GROUP BY` or `JOIN` in the same SQL statement.
:::
......
......@@ -53,11 +53,6 @@ window_clause: {
| STATE_WINDOW(col)
| INTERVAL(interval_val [, interval_offset]) [SLIDING (sliding_val)] [WATERMARK(watermark_val)] [FILL(fill_mod_and_val)]
changes_option: {
DURATION duration_val
| ROWS rows_val
}
group_by_clause:
GROUP BY expr [, expr] ... HAVING condition
......@@ -127,7 +122,6 @@ SELECT DISTINCT col_name [, col_name ...] FROM tb_name;
1. cfg 文件中的配置参数 maxNumOfDistinctRes 将对 DISTINCT 能够输出的数据行数进行限制。其最小值是 100000,最大值是 100000000,默认值是 10000000。如果实际计算结果超出了这个限制,那么会仅输出这个数量范围内的部分。
2. 由于浮点数天然的精度机制原因,在特定情况下,对 FLOAT 和 DOUBLE 列使用 DISTINCT 并不能保证输出值的完全唯一性。
3. 在当前版本下,DISTINCT 不能在嵌套查询的子查询中使用,也不能与聚合函数、GROUP BY、或 JOIN 在同一条语句中混用。
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