Support MySQL system variables (#3576)

* Modify at_sign lexer and add parser to handle MyQL system variables + provide fixtures for validation. * Improve at_sign lexer. $ sign is now supported, and a `.` cannot be at the start/end of a variable name. Co-authored-by: Barry Hart <barrywhart@yahoo.com>
sqlfluff · Jul 10, 2022 · faa1c83 · faa1c83
1 parent 50f0638
commit faa1c83
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Showing 5 changed files with 105 additions and 7 deletions.
diff --git a/src/sqlfluff/dialects/dialect_mysql.py b/src/sqlfluff/dialects/dialect_mysql.py
@@ -95,6 +95,7 @@
     LiteralGrammar=ansi_dialect.get_grammar("LiteralGrammar").copy(
         insert=[
             Ref("DoubleQuotedLiteralSegment"),
+            Ref("SystemVariableSegment"),
         ]
     ),
     FromClauseTerminatorGrammar=ansi_dialect.get_grammar(
@@ -208,6 +209,12 @@
         type="literal",
         trim_chars=("@",),
     ),
+    SystemVariableSegment=RegexParser(
+        r"@@(session|global)\.[A-Za-z0-9_]+",
+        CodeSegment,
+        name="system_variable",
+        type="system_variable",
+    ),
 )
 
 
@@ -684,13 +691,13 @@ class IntervalExpressionSegment(BaseSegment):
         Ref("DatatypeSegment"),
     ),
     LocalVariableNameSegment=RegexParser(
-        r"`?[a-zA-Z0-9_]*`?",
+        r"`?[a-zA-Z0-9_$]*`?",
         CodeSegment,
         name="declared_variable",
         type="variable",
     ),
     SessionVariableNameSegment=RegexParser(
-        r"[@][a-zA-Z0-9_]*",
+        r"[@][a-zA-Z0-9_$]*",
         CodeSegment,
         name="declared_variable",
         type="variable",
@@ -710,7 +717,7 @@ class IntervalExpressionSegment(BaseSegment):
     [
         RegexLexer(
             "at_sign",
-            r"[@][a-zA-Z0-9_]*",
+            r"@@?[a-zA-Z0-9_$]*(\.[a-zA-Z0-9_$]+)?",
             CodeSegment,
         ),
     ],

diff --git a/test/fixtures/dialects/mysql/set_session_variable.sql b/test/fixtures/dialects/mysql/set_session_variable.sql
@@ -1 +1,4 @@
-set @abc = 1;
+set @abc = 1;
+set @my_var = 1;
+set @my$currency = 1;
+set @sha256enabled = 1;
diff --git a/test/fixtures/dialects/mysql/set_session_variable.yml b/test/fixtures/dialects/mysql/set_session_variable.yml
@@ -3,13 +3,37 @@
 # computed by SQLFluff when running the tests. Please run
 # `python test/generate_parse_fixture_yml.py`  to generate them after adding or
 # altering SQL files.
-_hash: 91d7a5a3d6a5986cf93fd70ccbc2cc4f148a27c126ab479bc3d44f68690d4af3
+_hash: 9e4ffffc861f4647dfc51be1591f5df5931d712fe5083c39fde3ce9942d8ad60
 file:
-  statement:
+- statement:
     set_statement:
     - keyword: set
     - variable: '@abc'
     - comparison_operator:
         raw_comparison_operator: '='
     - variable: '1'
-  statement_terminator: ;
+- statement_terminator: ;
+- statement:
+    set_statement:
+    - keyword: set
+    - variable: '@my_var'
+    - comparison_operator:
+        raw_comparison_operator: '='
+    - variable: '1'
+- statement_terminator: ;
+- statement:
+    set_statement:
+    - keyword: set
+    - variable: '@my$currency'
+    - comparison_operator:
+        raw_comparison_operator: '='
+    - variable: '1'
+- statement_terminator: ;
+- statement:
+    set_statement:
+    - keyword: set
+    - variable: '@sha256enabled'
+    - comparison_operator:
+        raw_comparison_operator: '='
+    - variable: '1'
+- statement_terminator: ;
diff --git a/test/fixtures/dialects/mysql/system_variables.sql b/test/fixtures/dialects/mysql/system_variables.sql
@@ -0,0 +1,5 @@
+SELECT @@global.time_zone;
+SELECT @@session.time_zone;
+SELECT @@global.version;
+SELECT @@session.rand_seed1;
+SELECT CONVERT_TZ(NOW(), @@global.time_zone, '+00:00')
diff --git a/test/fixtures/dialects/mysql/system_variables.yml b/test/fixtures/dialects/mysql/system_variables.yml
@@ -0,0 +1,59 @@
+# YML test files are auto-generated from SQL files and should not be edited by
+# hand. To help enforce this, the "hash" field in the file must match a hash
+# computed by SQLFluff when running the tests. Please run
+# `python test/generate_parse_fixture_yml.py`  to generate them after adding or
+# altering SQL files.
+_hash: 7ee845cc79c4b19c5a15b765bf58282520be92649f543a90c3badb1900de89e4
+file:
+- statement:
+    select_statement:
+      select_clause:
+        keyword: SELECT
+        select_clause_element:
+          system_variable: '@@global.time_zone'
+- statement_terminator: ;
+- statement:
+    select_statement:
+      select_clause:
+        keyword: SELECT
+        select_clause_element:
+          system_variable: '@@session.time_zone'
+- statement_terminator: ;
+- statement:
+    select_statement:
+      select_clause:
+        keyword: SELECT
+        select_clause_element:
+          system_variable: '@@global.version'
+- statement_terminator: ;
+- statement:
+    select_statement:
+      select_clause:
+        keyword: SELECT
+        select_clause_element:
+          system_variable: '@@session.rand_seed1'
+- statement_terminator: ;
+- statement:
+    select_statement:
+      select_clause:
+        keyword: SELECT
+        select_clause_element:
+          function:
+            function_name:
+              function_name_identifier: CONVERT_TZ
+            bracketed:
+            - start_bracket: (
+            - expression:
+                function:
+                  function_name:
+                    function_name_identifier: NOW
+                  bracketed:
+                    start_bracket: (
+                    end_bracket: )
+            - comma: ','
+            - expression:
+                system_variable: '@@global.time_zone'
+            - comma: ','
+            - expression:
+                literal: "'+00:00'"
+            - end_bracket: )