Method convertAlterQuery

internal/engine/clickhouse/convert.go:944–1000

(n *chast.AlterQuery)

}

func (c *cc) convertAlterQuery(n *chast.AlterQuery) ast.Node {
	alt := &ast.AlterTableStmt{
		Table: &ast.TableName{
			Name: identifier(n.Table),
		},
		Cmds: &ast.List{},
	}

	if n.Database != "" {
		alt.Table.Schema = identifier(n.Database)
	}

	for _, cmd := range n.Commands {
		switch cmd.Type {
		case chast.AlterAddColumn:
			if cmd.Column != nil {
				name := cmd.Column.Name
				alt.Cmds.Items = append(alt.Cmds.Items, &ast.AlterTableCmd{
					Name:    &name,
					Subtype: ast.AT_AddColumn,
					Def:     c.convertColumnDeclaration(cmd.Column),
				})
			}
		case chast.AlterDropColumn:
			name := cmd.ColumnName
			alt.Cmds.Items = append(alt.Cmds.Items, &ast.AlterTableCmd{
				Name:      &name,
				Subtype:   ast.AT_DropColumn,
				MissingOk: cmd.IfExists,
			})
		case chast.AlterModifyColumn:
			if cmd.Column != nil {
				name := cmd.Column.Name
				// Drop and re-add to simulate modify
				alt.Cmds.Items = append(alt.Cmds.Items, &ast.AlterTableCmd{
					Name:    &name,
					Subtype: ast.AT_DropColumn,
				})
				alt.Cmds.Items = append(alt.Cmds.Items, &ast.AlterTableCmd{
					Name:    &name,
					Subtype: ast.AT_AddColumn,
					Def:     c.convertColumnDeclaration(cmd.Column),
				})
			}
		case chast.AlterRenameColumn:
			oldName := cmd.ColumnName
			newName := cmd.NewName
			return &ast.RenameColumnStmt{
				Table:   alt.Table,
				Col:     &ast.ColumnRef{Name: oldName},
				NewName: &newName,
			}
		}
	}

	return alt
}