func TestSelect_ColumnNames(t *testing.T) {
for i, tt := range []struct {
stmt *influxql.SelectStatement
columns []string
}{
{
stmt: &influxql.SelectStatement{
Fields: influxql.Fields([]*influxql.Field{
{Expr: &influxql.VarRef{Val: "value"}},
}),
},
columns: []string{"time", "value"},
},
{
stmt: &influxql.SelectStatement{
Fields: influxql.Fields([]*influxql.Field{
{Expr: &influxql.VarRef{Val: "value"}},
{Expr: &influxql.VarRef{Val: "value"}},
{Expr: &influxql.VarRef{Val: "value_1"}},
}),
},
columns: []string{"time", "value", "value_1", "value_1_1"},
},
{
stmt: &influxql.SelectStatement{
Fields: influxql.Fields([]*influxql.Field{
{Expr: &influxql.VarRef{Val: "value"}},
{Expr: &influxql.VarRef{Val: "value_1"}},
{Expr: &influxql.VarRef{Val: "value"}},
}),
},
columns: []string{"time", "value", "value_1", "value_2"},
},
{
stmt: &influxql.SelectStatement{
Fields: influxql.Fields([]*influxql.Field{
{Expr: &influxql.VarRef{Val: "value"}},
{Expr: &influxql.VarRef{Val: "total"}, Alias: "value"},
{Expr: &influxql.VarRef{Val: "value"}},
}),
},
columns: []string{"time", "value_1", "value", "value_2"},
},
{
stmt: &influxql.SelectStatement{
Fields: influxql.Fields([]*influxql.Field{
{Expr: &influxql.VarRef{Val: "value"}},
}),
TimeAlias: "timestamp",
},
columns: []string{"timestamp", "value"},
},
} {
columns := tt.stmt.ColumnNames()
if !reflect.DeepEqual(columns, tt.columns) {
t.Errorf("%d. expected %s, got %s", i, tt.columns, columns)
}
}
}
// planShowMeasurements converts the statement to a SELECT and executes it.
func (q *QueryExecutor) planShowMeasurements(stmt *influxql.ShowMeasurementsStatement, database string, chunkSize int) (Executor, error) {
// Check for time in WHERE clause (not supported).
if influxql.HasTimeExpr(stmt.Condition) {
return nil, errors.New("SHOW MEASUREMENTS doesn't support time in WHERE clause")
}
condition := stmt.Condition
if source, ok := stmt.Source.(*influxql.Measurement); ok {
var expr influxql.Expr
if source.Regex != nil {
expr = &influxql.BinaryExpr{
Op: influxql.EQREGEX,
LHS: &influxql.VarRef{Val: "name"},
RHS: &influxql.RegexLiteral{Val: source.Regex.Val},
}
} else if source.Name != "" {
expr = &influxql.BinaryExpr{
Op: influxql.EQ,
LHS: &influxql.VarRef{Val: "name"},
RHS: &influxql.StringLiteral{Val: source.Name},
}
}
// Set condition or "AND" together.
if condition == nil {
condition = expr
} else {
condition = &influxql.BinaryExpr{Op: influxql.AND, LHS: expr, RHS: condition}
}
}
ss := &influxql.SelectStatement{
Fields: influxql.Fields([]*influxql.Field{
{Expr: &influxql.VarRef{Val: "name"}},
}),
Sources: influxql.Sources([]influxql.Source{
&influxql.Measurement{Name: "_measurements"},
}),
Condition: condition,
Offset: stmt.Offset,
Limit: stmt.Limit,
SortFields: stmt.SortFields,
OmitTime: true,
Dedupe: true,
}
// Normalize the statement.
if err := q.normalizeStatement(ss, database); err != nil {
return nil, err
}
return q.PlanSelect(ss, chunkSize)
}