Fix strings for SHOW MEASUREMENTS

influxql/ast.go

@@ -1958,6 +1958,15 @@ func (s *ShowMeasurementsStatement) String() string {
 	var buf bytes.Buffer
 	_, _ = buf.WriteString("SHOW MEASUREMENTS")
 
+	if s.Source != nil {
+		_, _ = buf.WriteString(" WITH MEASUREMENT ")
+		if m, ok := s.Source.(*Measurement); ok && m.Regex != nil {
+			_, _ = buf.WriteString("=~ ")
+		} else {
+			_, _ = buf.WriteString("= ")
+		}
+		_, _ = buf.WriteString(s.Source.String())
+	}
 	if s.Condition != nil {
 		_, _ = buf.WriteString(" WHERE ")
 		_, _ = buf.WriteString(s.Condition.String())

influxql/ast_test.go

@@ -633,6 +633,12 @@ func TestParseString(t *testing.T) {
 		{
 			stmt: `CREATE SUBSCRIPTION "ugly \"subscription\" name" ON "\"my\" db"."\"my\" rp" DESTINATIONS ALL 'my host', 'my other host'`,
 		},
+		{
+			stmt: `SHOW MEASUREMENTS WITH MEASUREMENT =~ /foo/`,
+		},
+		{
+			stmt: `SHOW MEASUREMENTS WITH MEASUREMENT = "and/or"`,
+		},
 	}
 
 	for _, tt := range tests {
@@ -642,10 +648,14 @@ func TestParseString(t *testing.T) {
 			t.Fatalf("invalid statement: %q: %s", tt.stmt, err)
 		}
 
-		_, err = influxql.NewParser(strings.NewReader(stmt.String())).ParseStatement()
+		stmtCopy, err := influxql.NewParser(strings.NewReader(stmt.String())).ParseStatement()
 		if err != nil {
 			t.Fatalf("failed to parse string: %v\norig: %v\ngot: %v", err, tt.stmt, stmt.String())
 		}
+
+		if !reflect.DeepEqual(stmt, stmtCopy) {
+			t.Fatalf("statement changed after stringifying and re-parsing:\noriginal : %v\nre-parsed: %v\n", tt.stmt, stmtCopy.String())
+		}
 	}
 }