Merge pull request #2691 from dolthub/zachmu/show-table-schema

Bug fix for DESCRIBE with a schema name

Author: zachmu

sql/planbuilder/show.go

@@ -717,13 +717,18 @@ func (b *Builder) buildShowAllColumns(inScope *scope, s *ast.Show) (outScope *sc
 	}
 
 	var dbName string
+	var schemaName string
 	if s.ShowTablesOpt != nil && s.ShowTablesOpt.DbName != "" {
 		dbName = s.ShowTablesOpt.DbName
 	} else if s.Table.DbQualifier.String() != "" {
 		dbName = s.Table.DbQualifier.String()
 	}
 
-	tableScope, ok := b.buildResolvedTable(inScope, dbName, "", s.Table.Name.String(), asOf)
+	if s.ShowTablesOpt != nil && s.ShowTablesOpt.SchemaName != "" {
+		schemaName = s.ShowTablesOpt.SchemaName
+	}
+
+	tableScope, ok := b.buildResolvedTable(inScope, dbName, schemaName, s.Table.Name.String(), asOf)
 	if !ok {
 		err := sql.ErrTableNotFound.New(s.Table.Name.String())
 		b.handleErr(err)