结果包含与关系查询结果的来源和类型相关的元数据。需要处理动态查询结果或格式化结果以进行转换或显示的应用程序可以使用此元数据。结果元数据可通过Column. 可以使用该 getColumns()方法从任何 RowResult 获取列数组。

例如，响应查询返回以下元数据SELECT 1+1 AS a, b FROM mydb.some_table_with_b AS b_table。

Column[0].databaseName = NULL
Column[0].tableName = NULL
Column[0].tableLabel = NULL
Column[0].columnName = NULL
Column[0].columnLabel = "a"
Column[0].type = BIGINT
Column[0].length = 3
Column[0].fractionalDigits = 0
Column[0].numberSigned = TRUE
Column[0].collationName = "binary"
Column[0].characterSetName = "binary"
Column[0].padded = FALSE

Column[1].databaseName = "mydb"
Column[1].tableName = "some_table_with_b"
Column[1].tableLabel = "b_table"
Column[1].columnName = "b"
Column[1].columnLabel = "b"
Column[1].type = STRING
Column[1].length = 20 (e.g.)
Column[1].fractionalDigits = 0
Column[1].numberSigned = TRUE
Column[1].collationName = "utf8mb4_general_ci"
Column[1].characterSetName = "utf8mb4"
Column[1].padded = FALSE