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Posted to commits@drill.apache.org by br...@apache.org on 2017/11/14 18:02:53 UTC
drill git commit: dots in column names - lexical structure
Repository: drill
Updated Branches:
refs/heads/gh-pages b890be92b -> 37e280b8e
dots in column names - lexical structure
Project: http://git-wip-us.apache.org/repos/asf/drill/repo
Commit: http://git-wip-us.apache.org/repos/asf/drill/commit/37e280b8
Tree: http://git-wip-us.apache.org/repos/asf/drill/tree/37e280b8
Diff: http://git-wip-us.apache.org/repos/asf/drill/diff/37e280b8
Branch: refs/heads/gh-pages
Commit: 37e280b8eae649f2679dee38c68007052d082c3b
Parents: b890be9
Author: Bridget Bevens <bb...@maprtech.com>
Authored: Tue Nov 14 07:31:11 2017 -0800
Committer: Bridget Bevens <bb...@maprtech.com>
Committed: Tue Nov 14 07:31:11 2017 -0800
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_docs/sql-reference/030-lexical-structure.md | 30 +++++++++++++++++++----
1 file changed, 25 insertions(+), 5 deletions(-)
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http://git-wip-us.apache.org/repos/asf/drill/blob/37e280b8/_docs/sql-reference/030-lexical-structure.md
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diff --git a/_docs/sql-reference/030-lexical-structure.md b/_docs/sql-reference/030-lexical-structure.md
index 3e5a3f2..7ca96fd 100644
--- a/_docs/sql-reference/030-lexical-structure.md
+++ b/_docs/sql-reference/030-lexical-structure.md
@@ -1,6 +1,6 @@
---
title: "Lexical Structure"
-date: 2017-08-08 21:12:19 UTC
+date: 2017-11-14 15:31:15 UTC
parent: "SQL Reference"
---
@@ -78,7 +78,7 @@ If you have dates and times in other formats, use a [data type conversion functi
An identifier is a letter followed by any sequence of letters, digits, or the underscore. For example, names of tables, columns, and aliases are identifiers. Maximum length is 1024 characters. Enclose the following identifiers with identifier quotes:
* Keywords
-* Identifiers that SQL cannot parse
+* Identifiers that SQL cannot parse
For example, enclose the SQL keywords date and time in identifier quotes when referring to column names, but not when referring to data types:
@@ -92,7 +92,7 @@ For example, enclose the SQL keywords date and time in identifier quotes when re
Table and column names are case-insensitive. Use identifier quotes to enclose names that contain special characters. Special characters are those other than the 52 Latin alphabet characters. For example, space and @ are special characters.
-The following example shows the keyword Year enclosed in identifier quotes. Because the column alias contains the special space character, also enclose the alias in back ticks, as shown in the following example:
+The following example shows the keyword Year enclosed in identifier quotes. Because the column alias contains the special space character, also enclose the alias in backticks, as shown in the following example:
SELECT extract(year from transdate) AS `Year`, t.user_info.cust_id AS `Customer Number` FROM dfs.tmp.`sampleparquet` t;
+------------+-----------------+
@@ -108,7 +108,7 @@ The following example shows the keyword Year enclosed in identifier quotes. Beca
### Identifier Quotes
-Prior to Drill 1.11, the SQL parser in Drill only supported back ticks as identifier quotes. As of Drill 1.11, the SQL parser can also use double quotes and square brackets. The default setting for identifier quotes is back ticks. You can configure the type of identifier quotes used with the `planner.parser.quoting_identifiers` configuration option, at the system or session level, as shown:
+Prior to Drill 1.11, the SQL parser in Drill only supported backticks as identifier quotes. As of Drill 1.11, the SQL parser can also use double quotes and square brackets. The default setting for identifier quotes is backticks. You can configure the type of identifier quotes used with the `planner.parser.quoting_identifiers` configuration option, at the system or session level, as shown:
ALTER SYSTEM|SESSION SET planner.parser.quoting_identifiers = '"';
ALTER SYSTEM|SESSION SET planner.parser.quoting_identifiers = '[';
@@ -118,7 +118,7 @@ The following table lists the supported identifier quotes with their correspondi
| Quoting Identifier | Unicode Character |
|----------------------|-----------------------------------------------------------------------|
-| Back ticks | 'GRAVE ACCENT' (U+0060) |
+| Backticks | 'GRAVE ACCENT' (U+0060) |
| Double quotes | 'QUOTATION MARK' (U+0022) |
| Square brackets | 'LEFT SQUARE BRACKET' (U+005B) and 'RIGHT SQUARE BRACKET' (U+005D) |
@@ -154,6 +154,26 @@ The following queries show the use of each type of identifier quotes:
+--------------+---------------+
1 row selected (0.14 seconds)
+### Dots in Column Names
+As of Drill 1.12, Drill supports dots in column names if the data source itself allows dots in column names, such as JSON and Parquet , as shown in the following example:
+
+ SELECT * FROM `test.json`;
+
+ +--------------------------------------------------------+----------------------------------------------------------+
+ | 0.0.1 | 0.1.2 |
+ +--------------------------------------------------------+----------------------------------------------------------+
+ | {"version":"0.0.1","date_created":"2014-03-15"} | {"version":"0.1.2","date_created":"2014-05-21"} |
+ +--------------------------------------------------------+----------------------------------------------------------+
+
+When referencing column names with dots in queries, you must escape the dots with [identifier quotes]({{site.baseurl}}/docs/lexical-structure/#identifier-quotes), as shown in the following query:
+
+ SELECT t.`0.1.2`.version FROM dfs.tmp.`test.json` t WHERE t.`0.1.2`.date_created='2014-05-21'
+
+Drill also supports associative array indexing, for example `SELECT a, b.c, b['d.e']...`.
+
+Note that in this example, the `“d.e”` field is selected, not a map `“d”` with field `“e”` inside of it.
+
+
### Integer
An integer value consists of an optional minus sign, -, followed by one or more digits.