From 82684bb4179ca3aa918ddec9c76f4810bc9135b2 Mon Sep 17 00:00:00 2001 From: gccgdb1234 Date: Tue, 20 Sep 2022 09:39:55 +0800 Subject: [PATCH] doc: refine a few points in 06-select.md --- docs/en/12-taos-sql/06-select.md | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/docs/en/12-taos-sql/06-select.md b/docs/en/12-taos-sql/06-select.md index 118a248373..e409973173 100644 --- a/docs/en/12-taos-sql/06-select.md +++ b/docs/en/12-taos-sql/06-select.md @@ -66,7 +66,7 @@ order_expr: A query can be performed on some or all columns. Data and tag columns can all be included in the SELECT list. -## Wildcards +### Wildcards You can use an asterisk (\*) as a wildcard character to indicate all columns. For standard tables, the asterisk indicates only data columns. For supertables and subtables, tag columns are also included. @@ -136,6 +136,8 @@ taos> SELECT ts, ts AS primary_key_ts FROM d1001; ### Pseudocolumns +**Pseudocolumn:** A pseudo-column behaves like a table column but is not actually stored in the table. You can select from pseudo-columns, but you cannot insert, update, or delete their values. A pseudo-column is also similar to a function without arguments. This section describes these pseudo-columns: + **TBNAME** The TBNAME pseudocolumn in a supertable contains the names of subtables within the supertable.