parser: ast/expressions.go: IsNullExpr (pingcap#72)

tiancaiamao · Dec 8, 2018 · f39a9bb · f39a9bb
1 parent 30aca86
commit f39a9bb
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/ast/expressions.go b/ast/expressions.go
@@ -605,7 +605,8 @@ type IsNullExpr struct {
 
 // Restore implements Recoverable interface.
 func (n *IsNullExpr) Restore(sb *strings.Builder) error {
-	return errors.New("Not implemented")
+	n.Format(sb)
+	return nil
 }
 
 // Format the ExprNode into a Writer.

diff --git a/ast/expressions_test.go b/ast/expressions_test.go
@@ -131,11 +131,19 @@ func (tc *testExpressionsSuite) createTestCase4ColumnNameExpr() []exprTestCase {
 	}
 }
 
+func (tc *testExpressionsSuite) createTestCase4IsNullExpr() []exprTestCase {
+	return []exprTestCase{
+		{"select a is null", "SELECT `a` IS NULL"},
+		{"select a is not null", "SELECT `a` IS NOT NULL"},
+	}
+}
+
 func (tc *testExpressionsSuite) TestExpresionsRestore(c *C) {
 	parser := parser.New()
 	var testNodes []exprTestCase
 	testNodes = append(testNodes, tc.createTestCase4UnaryOperationExpr()...)
 	testNodes = append(testNodes, tc.createTestCase4ColumnNameExpr()...)
+	testNodes = append(testNodes, tc.createTestCase4IsNullExpr()...)
 
 	for _, node := range testNodes {
 		stmt, err := parser.ParseOneStmt(node.sourceSQL, "", "")