deal with subquery in where clause (#54)

Author: joe-re

packages/sql-parser/base/fromClauseParser.js

@@ -752,6 +752,7 @@ primary
       e.paren = true; 
       return e; 
     } 
+  / select_stmt
   / var_decl
 
 column_ref 

packages/sql-parser/base/parser.js

@@ -0,0 +1,16 @@
+const { parse } = require('../index')
+
+describe('Subquery in where clause', () => {
+ it('should success to parse', () => {
+    const sql = `
+      SELECT *
+      FROM T1
+      WHERE T1.num = (SELECT max(T2.num) from T2)
+    `
+     const result = parse(sql)
+     expect(result).toBeDefined()
+     expect(result).toMatchObject({ type: 'select' })
+     expect(result.where.expression.left).toMatchObject({ type: 'column_ref' })
+     expect(result.where.expression.right).toMatchObject({ type: 'select' })
+  })
+})