Merge pull request #2001 from taozhi8833998/feat-explain-stmt-mysql

feat: support explain stmt in mysql

pegjs/mariadb.pegjs

@@ -248,6 +248,7 @@ cmd_stmt
   / show_stmt
   / desc_stmt
   / grant_stmt
+  / explain_stmt
 
 create_stmt
   = create_table_stmt
@@ -1663,6 +1664,18 @@ desc_stmt
     };
   }
 
+explain_stmt
+  = KW_EXPLAIN __ t:select_stmt_nake {
+    return {
+      tableList: Array.from(tableList),
+      columnList: columnListTableAlias(columnList),
+      ast: {
+        type: 'explain',
+        expr: t
+      }
+    }
+  }
+
 lock_type
   = "READ"i __ s:("LOCAL"i)? {
     return {

pegjs/mysql.pegjs

@@ -445,6 +445,7 @@ cmd_stmt
   / show_stmt
   / desc_stmt
   / grant_stmt
+  / explain_stmt
 
 create_stmt
   = create_table_stmt
@@ -1938,6 +1939,18 @@ desc_stmt
     };
   }
 
+explain_stmt
+  = KW_EXPLAIN __ t:select_stmt_nake {
+    return {
+      tableList: Array.from(tableList),
+      columnList: columnListTableAlias(columnList),
+      ast: {
+        type: 'explain',
+        expr: t
+      }
+    }
+  }
+
 priv_type_table
   =  p:(KW_ALL / KW_ALTER / KW_CREATE __ 'VIEW'i / KW_CREATE / KW_DELETE / KW_DROP / 'GRANT'i __ 'OPTION'i / KW_INDEX / KW_INSERT / KW_REFERENCES / KW_SELECT / KW_SHOW __ KW_VIEW / KW_TRIGGER / KW_UPDATE) {
     return {

src/explain.js

@@ -0,0 +1,11 @@
+import { selectToSQL } from './select'
+import { toUpper } from './util'
+
+function explainToSQL(stmt) {
+  const { type, expr } = stmt
+  return [toUpper(type), selectToSQL(expr)].join(' ')
+}
+
+export {
+  explainToSQL,
+}

src/sql.js

@@ -1,6 +1,6 @@
 import { unionToSQL, multipleToSQL } from './union'
 
-const supportedTypes = ['analyze', 'attach', 'select', 'deallocate', 'delete', 'exec', 'update', 'insert', 'drop', 'rename', 'truncate', 'call', 'desc', 'use', 'alter', 'set', 'create', 'lock', 'unlock', 'declare', 'show', 'replace', 'if', 'grant', 'revoke', 'proc', 'raise', 'execute', 'transaction']
+const supportedTypes = ['analyze', 'attach', 'select', 'deallocate', 'delete', 'exec', 'update', 'insert', 'drop', 'rename', 'truncate', 'call', 'desc', 'use', 'alter', 'set', 'create', 'lock', 'unlock', 'declare', 'show', 'replace', 'if', 'grant', 'revoke', 'proc', 'raise', 'execute', 'transaction', 'explain']
 
 function checkSupported(expr) {
   const ast = expr && expr.ast ? expr.ast : expr

src/union.js

@@ -1,6 +1,7 @@
 import { alterToSQL } from './alter'
 import { analyzeToSQL, attachToSQL } from './analyze'
 import { createToSQL } from './create'
+import { explainToSQL } from './explain'
 import { selectToSQL } from './select'
 import { deleteToSQL } from './delete'
 import { updateToSQL } from './update'
@@ -39,6 +40,7 @@ const typeToSQLFn = {
   delete      : deleteToSQL,
   exec        : execToSQL,
   execute     : executeToSQL,
+  explain     : explainToSQL,
   for         : forLoopToSQL,
   update      : updateToSQL,
   if          : ifToSQL,

test/mysql-mariadb.spec.js

@@ -1064,12 +1064,19 @@ describe('mysql', () => {
         ]
       },
       {
-        title: 'collate2',
+        title: 'collate with symbol and value',
         sql: [
           'select * from test where id COLLATE utf8mb4_unicode_ci = abc',
           'SELECT * FROM `test` WHERE `id` COLLATE utf8mb4_unicode_ci = abc'
         ]
       },
+      {
+        title: 'explain stmt',
+        sql: [
+          'EXPLAIN SELECT * FROM incidents where id > 10 and is_delete = 0',
+          'EXPLAIN SELECT * FROM `incidents` WHERE `id` > 10 AND `is_delete` = 0'
+        ]
+      },
     ]
     SQL_LIST.forEach(sqlInfo => {
       const { title, sql } = sqlInfo