feat(print-statements): intercept explain query plan statements

Author: douglasmdev

internal/db/db.go

@@ -223,15 +223,16 @@ func getColumnTypes(rows *sql.Rows) ([]reflect.Type, error) {
 
 func readQueryResults(queryRows *sql.Rows, statementResultCh chan StatementResult, query string) (shouldContinue bool) {
 	queries, _ := sqliteparserutils.SplitStatement(query)
+	queryIndex := 0
 	hasResultSetToRead := true
 	for hasResultSetToRead {
-		for _, query := range queries {
-			if shouldContinue := readQueryResultSet(queryRows, statementResultCh, query); !shouldContinue {
-				return false
-			}
-
-			hasResultSetToRead = queryRows.NextResultSet()
+		query := queries[queryIndex]
+		if shouldContinue := readQueryResultSet(queryRows, statementResultCh, query); !shouldContinue {
+			return false
 		}
+
+		hasResultSetToRead = queryRows.NextResultSet()
+		queryIndex++
 	}
 
 	if err := queryRows.Err(); err != nil {

internal/db/output.go

@@ -21,7 +21,8 @@ type TablePrinter struct {
 func (t TablePrinter) print(statementResult StatementResult, outF io.Writer) error {
 	data := [][]string{}
 	table := createTable(outF)
-	if !t.withoutHeader {
+	showHeader := !IsResultComingFromExplainQueryPlan(statementResult) && !t.withoutHeader
+	if showHeader {
 		table.SetHeader(statementResult.ColumnNames)
 	}
 
@@ -100,6 +101,11 @@ func appendData(statementResult StatementResult, data [][]string, mode FormatTyp
 		}
 		data = append(data, formattedRow)
 	}
+
+	if IsResultComingFromExplainQueryPlan(statementResult) {
+		data = [][]string{{"Tree goes here!"}}
+	}
+
 	return data, nil
 }
 

internal/db/utils.go

@@ -2,6 +2,7 @@ package db
 
 import (
 	"net/url"
+	"reflect"
 	"strings"
 	"unicode"
 )
@@ -45,3 +46,25 @@ func NeedsEscaping(name string) bool {
 	}
 	return false
 }
+
+var explainQueryPlanStatement = "EXPLAIN QUERY PLAN"
+var explainQueryPlanColumnNames = []string{"id", "parent", "notused", "detail"}
+
+func queryContainsExplainQueryPlanStatement(query string) bool {
+	return strings.HasPrefix(
+		strings.ToLower(query),
+		strings.ToLower(explainQueryPlanStatement),
+	)
+}
+
+func columnNamesMatchExplainQueryPlan(colNames []string) bool {
+	return reflect.DeepEqual(colNames, explainQueryPlanColumnNames)
+}
+
+// "query" can be a string containing multiple queries separated by ";" or a single query
+func IsResultComingFromExplainQueryPlan(statementResult StatementResult) bool {
+	query := statementResult.Query
+	columnNames := statementResult.ColumnNames
+	return queryContainsExplainQueryPlanStatement(query) &&
+		columnNamesMatchExplainQueryPlan(columnNames)
+}

test/db_root_command_shell_test.go

@@ -271,6 +271,19 @@ func (s *DBRootCommandShellSuite) Test_GivenATableNameWithSpecialCharacters_When
 	s.tc.AssertSqlEquals(outS, expected)
 }
 
+func (s *DBRootCommandShellSuite) Test_GivenATableNameWithTheSameSignatureAsExpainQueryPlan_WhenChainingItWithExplainQueryPlan_ExpectCorrectData() {
+	_, _, err := s.tc.Execute("CREATE TABLE fake_explain (ID INTEGER PRIMARY KEY, PARENT INTEGER, NOTUSED INTEGER, DETAIL TEXT)")
+	s.tc.Assert(err, qt.IsNil)
+
+	outS, errS, err := s.tc.ExecuteShell([]string{"SELECT * FROM fake_explain; EXPLAIN QUERY PLAN SELECT 1;"})
+	s.tc.Assert(err, qt.IsNil)
+	s.tc.Assert(errS, qt.Equals, "")
+
+	expected := "id     parent     notused     detail \ntree goes here!"
+
+	s.tc.AssertSqlEquals(outS, expected)
+}
+
 func (s *DBRootCommandShellSuite) Test_GivenATableWithRecordsWithSingleQuote_WhenCalllSelectAllFromTable_ExpectSingleQuoteScape() {
 	s.tc.CreateEmptySimpleTable("t")
 	_, errS, err := s.tc.Execute("INSERT INTO t VALUES (0, \"x'x\", 0)")