如果特定列值重复，则为行联合

Question

例如，我有3个表：

  

table1（id，value）table2（id，fk，value）table3（id，fk，value）

table2和table3是table1的子项。

我有以下SQL查询：

query = "SELECT" +
            " t1.id AS _id," +
            " t2.id AS t2_id," +
            " t2.fk as t2_fk," +
            " t2.value as t2_value," +
            " t3.id AS t3_id," +
            " t3.fk as t3_fk," +
            " t3.value as t3_value," +
            " FROM t1 table1" +
            "     INNER JOIN table2 t2 ON t1.id = t2.fk" +
            "     INNER JOIN table3 t3 ON t1.id = t3.fk" +
            " WHERE t2.value like '%"+lookingFor+"%' LIMIT 10";

光标给出以下结果：

如何做到这一点：

我的目的是避免重复值，同时在一个地方收集所有t3_value。我怎么能实现这个目标？

Answer 1

试试这个：

query = "SELECT" +
            " t1.id AS _id," +
            " t2.id AS t2_id," +
            " t2.fk as t2_fk," +
            " t2.value as t2_value," +
            " GROUP_CONCAT(t3.value) as t3_value," +
            " FROM t1 table1" +
            "     INNER JOIN table2 t2 ON t1.id = t2.fk" +
            "     INNER JOIN table3 t3 ON t1.id = t3.fk" +
            " WHERE t2.value like '%"+lookingFor+"%'
            GROUP BY t1.id, t2.id, t2.fk, t2.value  LIMIT 10 ";

并了解您想要的是“GROUP_CONCAT（X，Y）” - 部分参考here。