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sql: make the table reference syntax carry its alias, if any #17031

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merged 1 commit into from
Jul 18, 2017
Merged

sql: make the table reference syntax carry its alias, if any #17031

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103 changes: 55 additions & 48 deletions pkg/sql/data_source.go
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Original file line number Diff line number Diff line change
Expand Up @@ -387,22 +387,17 @@ func (p *planner) getDataSource(
case *parser.ParenTableExpr:
return p.getDataSource(ctx, t.Expr, hints, scanVisibility)

case *parser.TableRef:
return p.getTableScanByRef(ctx, t, hints, scanVisibility)

case *parser.AliasedTableExpr:
// Alias clause: source AS alias(cols...)

var src planDataSource
var err error

if t.Hints != nil {
hints = t.Hints
}

if tref, ok := t.Expr.(*parser.TableRef); ok {
// Special case: operand is a numeric table reference.
src, err = p.getTableScanByRef(ctx, tref, hints, scanVisibility)
} else {
src, err = p.getDataSource(ctx, t.Expr, hints, scanVisibility)
}
src, err := p.getDataSource(ctx, t.Expr, hints, scanVisibility)
if err != nil {
return src, err
}
Expand All @@ -415,43 +410,7 @@ func (p *planner) getDataSource(
src = p.wrapOrdinality(src)
}

var tableAlias parser.TableName
if t.As.Alias != "" {
// If an alias was specified, use that.
tableAlias.TableName = t.As.Alias
src.info.sourceAliases = sourceAliases{{
name: tableAlias,
columnRange: fillColumnRange(0, len(src.info.sourceColumns)-1),
}}
}
colAlias := t.As.Cols

if len(colAlias) > 0 {
// Make a copy of the slice since we are about to modify the contents.
src.info.sourceColumns = append(sqlbase.ResultColumns(nil), src.info.sourceColumns...)

// The column aliases can only refer to explicit columns.
for colIdx, aliasIdx := 0, 0; aliasIdx < len(colAlias); colIdx++ {
if colIdx >= len(src.info.sourceColumns) {
var srcName string
if tableAlias.DatabaseName != "" {
srcName = tableAlias.String()
} else {
srcName = tableAlias.TableName.String()
}

return planDataSource{}, errors.Errorf(
"source %q has %d columns available but %d columns specified",
srcName, aliasIdx, len(colAlias))
}
if src.info.sourceColumns[colIdx].Hidden {
continue
}
src.info.sourceColumns[colIdx].Name = string(colAlias[aliasIdx])
aliasIdx++
}
}
return src, nil
return renameSource(src, t.As, false)

default:
return planDataSource{}, errors.Errorf("unsupported FROM type %T", src)
Expand Down Expand Up @@ -486,7 +445,7 @@ func (p *planner) getTableScanByRef(
}
desc, err := descFunc(ctx, p.txn, tableID)
if err != nil {
return planDataSource{}, err
return planDataSource{}, errors.Errorf("%s: %v", parser.ErrString(tref), err)
}

tn := parser.TableName{
Expand All @@ -502,7 +461,55 @@ func (p *planner) getTableScanByRef(
DBNameOriginallyOmitted: true,
}

return p.getPlanForDesc(ctx, desc, &tn, hints, scanVisibility, tref.Columns)
src, err := p.getPlanForDesc(ctx, desc, &tn, hints, scanVisibility, tref.Columns)
if err != nil {
return src, err
}

return renameSource(src, tref.As, true)
}

// renameSource applies an AS clause to a data source.
func renameSource(
src planDataSource, as parser.AliasClause, includeHidden bool,
) (planDataSource, error) {
var tableAlias parser.TableName
if as.Alias != "" {
// If an alias was specified, use that.
tableAlias.TableName = as.Alias
src.info.sourceAliases = sourceAliases{{
name: tableAlias,
columnRange: fillColumnRange(0, len(src.info.sourceColumns)-1),
}}
}
colAlias := as.Cols

if len(colAlias) > 0 {
// Make a copy of the slice since we are about to modify the contents.
src.info.sourceColumns = append(sqlbase.ResultColumns(nil), src.info.sourceColumns...)

// The column aliases can only refer to explicit columns.
for colIdx, aliasIdx := 0, 0; aliasIdx < len(colAlias); colIdx++ {
if colIdx >= len(src.info.sourceColumns) {
var srcName string
if tableAlias.DatabaseName != "" {
srcName = parser.ErrString(&tableAlias)
} else {
srcName = parser.ErrString(tableAlias.TableName)
}

return planDataSource{}, errors.Errorf(
"source %q has %d columns available but %d columns specified",
srcName, aliasIdx, len(colAlias))
}
if !includeHidden && src.info.sourceColumns[colIdx].Hidden {
continue
}
src.info.sourceColumns[colIdx].Name = string(colAlias[aliasIdx])
aliasIdx++
}
}
return src, nil
}

// getTableScanOrViewPlan builds a planDataSource from a single data source
Expand Down
16 changes: 8 additions & 8 deletions pkg/sql/parser/parse_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -591,16 +591,16 @@ func TestParse(t *testing.T) {
{`SELECT * FROM (VALUES (1, 2)) AS foo`},
{`SELECT * FROM (VALUES (1, 2)) AS foo (a, b)`},

{`SELECT * FROM [123] AS t`},
{`SELECT * FROM [123(1, 2, 3)] AS t`},
{`SELECT * FROM [123()] AS t`},
{`SELECT * FROM [123 AS t]`},
{`SELECT * FROM [123(1, 2, 3) AS t]`},
{`SELECT * FROM [123() AS t]`},
{`SELECT * FROM t@[123]`},
{`SELECT * FROM t@{FORCE_INDEX=[123],NO_INDEX_JOIN}`},
{`SELECT * FROM [123]@[456] AS t`},
{`SELECT * FROM [123]@{FORCE_INDEX=[456],NO_INDEX_JOIN} AS t`},
{`SELECT * FROM [123 AS t]@[456]`},
{`SELECT * FROM [123 AS t]@{FORCE_INDEX=[456],NO_INDEX_JOIN}`},

// TODO(pmattis): Is this a postgres extension?
{`TABLE a`}, // Shorthand for: SELECT * FROM a
{`TABLE a`}, // Shorthand for: SELECT * FROM a; used e.g. in CREATE VIEW v AS TABLE t
{`TABLE [123 AS a]`},

{`TRUNCATE TABLE a`},
{`TRUNCATE TABLE a, b.c`},
Expand Down Expand Up @@ -748,7 +748,7 @@ func TestParse2(t *testing.T) {
`SELECT 'a' FROM t@{FORCE_INDEX=bar,NO_INDEX_JOIN}`},

{`SELECT 'a' FROM t@{FORCE_INDEX=[123]}`, `SELECT 'a' FROM t@[123]`},
{`SELECT 'a' FROM [123]@{FORCE_INDEX=[456]} AS t`, `SELECT 'a' FROM [123]@[456] AS t`},
{`SELECT 'a' FROM [123 AS t]@{FORCE_INDEX=[456]}`, `SELECT 'a' FROM [123 AS t]@[456]`},

{`SELECT a FROM t WHERE a IS UNKNOWN`, `SELECT a FROM t WHERE a IS NULL`},
{`SELECT a FROM t WHERE a IS NOT UNKNOWN`, `SELECT a FROM t WHERE a IS NOT NULL`},
Expand Down
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