forked from vitessio/vitess
/
query_gen.go
132 lines (118 loc) · 3.89 KB
/
query_gen.go
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// Copyright 2014, Google Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package planbuilder
import (
"github.com/youtube/vitess/go/vt/sqlparser"
"github.com/youtube/vitess/go/vt/vttablet/tabletserver/schema"
)
// GenerateFullQuery generates the full query from the ast.
func GenerateFullQuery(statement sqlparser.Statement) *sqlparser.ParsedQuery {
buf := sqlparser.NewTrackedBuffer(nil)
statement.Format(buf)
return buf.ParsedQuery()
}
// GenerateFieldQuery generates a query to just fetch the field info
// by adding impossible where clauses as needed.
func GenerateFieldQuery(statement sqlparser.Statement) *sqlparser.ParsedQuery {
buf := sqlparser.NewTrackedBuffer(sqlparser.FormatImpossibleQuery).WriteNode(statement)
if buf.HasBindVars() {
return nil
}
return buf.ParsedQuery()
}
// GenerateLimitQuery generates a select query with a limit clause.
func GenerateLimitQuery(selStmt sqlparser.SelectStatement) *sqlparser.ParsedQuery {
buf := sqlparser.NewTrackedBuffer(nil)
switch sel := selStmt.(type) {
case *sqlparser.Select:
limit := sel.Limit
if limit == nil {
sel.Limit = execLimit
defer func() {
sel.Limit = nil
}()
}
case *sqlparser.Union:
// Code is identical to *Select, but this one is a *Union.
limit := sel.Limit
if limit == nil {
sel.Limit = execLimit
defer func() {
sel.Limit = nil
}()
}
}
buf.Myprintf("%v", selStmt)
return buf.ParsedQuery()
}
// GenerateInsertOuterQuery generates the outer query for inserts.
func GenerateInsertOuterQuery(ins *sqlparser.Insert) *sqlparser.ParsedQuery {
buf := sqlparser.NewTrackedBuffer(nil)
buf.Myprintf("insert %v%sinto %v%v values %a",
ins.Comments,
ins.Ignore,
ins.Table,
ins.Columns,
":#values",
)
return buf.ParsedQuery()
}
// GenerateLoadMessagesQuery generates the query to load messages after insert.
func GenerateLoadMessagesQuery(ins *sqlparser.Insert) *sqlparser.ParsedQuery {
buf := sqlparser.NewTrackedBuffer(nil)
buf.Myprintf("select time_next, epoch, id, message from %v where %a", ins.Table, ":#pk")
return buf.ParsedQuery()
}
// GenerateUpdateOuterQuery generates the outer query for updates.
func GenerateUpdateOuterQuery(upd *sqlparser.Update) *sqlparser.ParsedQuery {
buf := sqlparser.NewTrackedBuffer(nil)
buf.Myprintf("update %v%v set %v where %a", upd.Comments, upd.Table, upd.Exprs, ":#pk")
return buf.ParsedQuery()
}
// GenerateDeleteOuterQuery generates the outer query for deletes.
func GenerateDeleteOuterQuery(del *sqlparser.Delete) *sqlparser.ParsedQuery {
buf := sqlparser.NewTrackedBuffer(nil)
buf.Myprintf("delete %vfrom %v where %a", del.Comments, del.Table, ":#pk")
return buf.ParsedQuery()
}
// GenerateUpdateSubquery generates the subquery for updats.
func GenerateUpdateSubquery(upd *sqlparser.Update, table *schema.Table) *sqlparser.ParsedQuery {
return GenerateSubquery(
table.Indexes[0].Columns,
upd.Table,
upd.Where,
upd.OrderBy,
upd.Limit,
true,
)
}
// GenerateDeleteSubquery generates the subquery for deletes.
func GenerateDeleteSubquery(del *sqlparser.Delete, table *schema.Table) *sqlparser.ParsedQuery {
return GenerateSubquery(
table.Indexes[0].Columns,
&sqlparser.AliasedTableExpr{Expr: del.Table},
del.Where,
del.OrderBy,
del.Limit,
true,
)
}
// GenerateSubquery generates a subquery based on the input parameters.
func GenerateSubquery(columns []sqlparser.ColIdent, table *sqlparser.AliasedTableExpr, where *sqlparser.Where, order sqlparser.OrderBy, limit *sqlparser.Limit, forUpdate bool) *sqlparser.ParsedQuery {
buf := sqlparser.NewTrackedBuffer(nil)
if limit == nil {
limit = execLimit
}
buf.WriteString("select ")
prefix := ""
for _, c := range columns {
buf.Myprintf("%s%v", prefix, c)
prefix = ", "
}
buf.Myprintf(" from %v%v%v%v", table, where, order, limit)
if forUpdate {
buf.Myprintf(sqlparser.ForUpdateStr)
}
return buf.ParsedQuery()
}