见类 DbExpr
data class DbExpr(public val exp:CharSequence /* 表达式, 可以是 String | DbQueryBuilder */,
public val alias:String?, /* 别名 */
public val expQuoting:Boolean = (exp !is IDbQueryBuilder) /* 是否转义exp, 只要不是子查询, 默认都转 */
) : CharSequence by ""
主要有两个作用:
- 带别名
DbQueryBuilder().select(DbExpr("username", "u"), DbExpr("password", "p")).from("user");
- 控制是否转义
DbQueryBuilder().select("username", DbExpr("COUNT(
id)", "total_posts", false))