fix(mysql): support IF EXISTS/IF NOT EXISTS in trigger/revoke syntax (#60)

* feat(snowflake): sync upstream grammar and fix task scripting parse

* fix(mysql): support IF EXISTS/IF NOT EXISTS revoke/trigger forms

* test(mysql): move IF EXISTS fixture SQL into existing example files

Author: h3n4l

mysql/MySQLParser.g4

@@ -700,7 +700,7 @@ viewSuid:
 ;
 
 createTrigger:
-    definerClause? TRIGGER_SYMBOL triggerName timing = (BEFORE_SYMBOL | AFTER_SYMBOL) event = (
+    definerClause? TRIGGER_SYMBOL ifNotExists? triggerName timing = (BEFORE_SYMBOL | AFTER_SYMBOL) event = (
         INSERT_SYMBOL
         | UPDATE_SYMBOL
         | DELETE_SYMBOL
@@ -1883,15 +1883,19 @@ renameUser:
 ;
 
 revoke:
-    REVOKE_SYMBOL (
+    REVOKE_SYMBOL ifExists? (
         roleOrPrivilegesList FROM_SYMBOL userList
         | roleOrPrivilegesList onTypeTo FROM_SYMBOL userList
         | ALL_SYMBOL PRIVILEGES_SYMBOL? (
             ON_SYMBOL aclType? grantIdentifier
             | COMMA_SYMBOL GRANT_SYMBOL OPTION_SYMBOL FROM_SYMBOL userList
         )
         | PROXY_SYMBOL ON_SYMBOL user FROM_SYMBOL userList
-    )
+    ) ignoreUnknownUser?
+;
+
+ignoreUnknownUser:
+    IGNORE_SYMBOL UNKNOWN_SYMBOL USER_SYMBOL
 ;
 
 onTypeTo: // Optional, starting with 8.0.1.

mysql/examples/ddl_create.sql

@@ -317,6 +317,7 @@ create definer = current_user() trigger trg_my2 after insert on test.t2 for each
 -- Create trigger 3
 -- delimiter //
 CREATE TRIGGER mask_private_data BEFORE INSERT ON users FOR EACH ROW BEGIN SET NEW.phone = CONCAT('555', NEW.id); END; -- //-- delimiter ;
+CREATE TRIGGER IF NOT EXISTS `my_trigger` BEFORE INSERT ON `my_table` FOR EACH ROW BEGIN SET NEW.my_col = CONCAT(NEW.mycol, NEW.id); END;
 #end
 #begin
 -- Create trigger 4
@@ -650,4 +651,4 @@ WITH my_values(val1, val2) AS (
 )
 SELECT v.val1, v.val2 FROM my_values v;
 #end
-;
+;

mysql/examples/grant.sql

@@ -98,6 +98,8 @@ GRANT FLUSH_OPTIMIZER_COSTS, FLUSH_STATUS, FLUSH_TABLES, FLUSH_USER_RESOURCES, P
 REVOKE reader FROM 'mysqluser'@'localhost';
 REVOKE reader FROM topreader;
 REVOKE `cloudsqlsuperuser`@`%` FROM `sarmonitoring`@`10.90.29.%`;
+REVOKE IF EXISTS SELECT ON test.t1 FROM jerry@localhost;
+REVOKE IF EXISTS Bogus ON test FROM jerry@localhost IGNORE UNKNOWN USER;
 -- Set Role
 SET ROLE DEFAULT;
 SET ROLE 'role1', 'role2';
@@ -107,4 +109,4 @@ SET ROLE ALL EXCEPT 'role1', 'role2';
 SET DEFAULT ROLE 'admin', 'developer' TO 'joe'@'10.0.0.1';
 SET DEFAULT ROLE `admin`@'%' to `dt_user`@`%`;
 -- MySQL on Amazon RDS
-GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, RELOAD, PROCESS, REFERENCES, INDEX, ALTER, SHOW DATABASES, CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE, REPLICATION SLAVE, REPLICATION CLIENT, CREATE VIEW, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE, CREATE USER, EVENT, TRIGGER, LOAD FROM S3, SELECT INTO S3, INVOKE LAMBDA ON *.* TO 'debezium_user'@'127.0.0.1';
+GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, RELOAD, PROCESS, REFERENCES, INDEX, ALTER, SHOW DATABASES, CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE, REPLICATION SLAVE, REPLICATION CLIENT, CREATE VIEW, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE, CREATE USER, EVENT, TRIGGER, LOAD FROM S3, SELECT INTO S3, INVOKE LAMBDA ON *.* TO 'debezium_user'@'127.0.0.1';