Question

Delete from employee_salary
where emp_id in(
          select emp_id from
          employee_salary 
          group by emp_id,project,salary 
          having count(*)>1
);
ERROR 1093 (HY000): You can't specify target table 'employee_salary' for update in FROM clause

如何解决此问题以及此查询为何也在运行？

Answer 1

这里的一个选项是将子查询包装在另一个子查询中：

import scala.concurrent.duration._

import io.gatling.core.Predef._
import io.gatling.http.Predef._
import io.gatling.jdbc.Predef._

class RecordedSimulation extends Simulation {

    val httpProtocol = http
        .baseURL("baseURL")
        .inferHtmlResources()

    val headers_0 = Map(
        "accept" -> "*/*",
        "accept-encoding" -> "gzip, deflate, br",
        "accept-language" -> "en-US,en;q=0.9",
        "access-control-request-headers" -> "access-control-allow-origin,authorization,content-type",
        "access-control-request-method" -> "GET",
        "origin" -> "URL_LINK",
        "user-agent" -> "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36")

    val headers_1 = Map(
        "accept" -> "*/*",
        "accept-encoding" -> "gzip, deflate, br",
        "accept-language" -> "en-US,en;q=0.9",
        "access-control-allow-origin" -> "*",
        **"authorization" -> "Need to pass value from the terminal while running the gatling.sh",**
        "content-type" -> "application/json",
        "origin" -> "ORIGIN_URL",
        "referer" -> "REFERER_URL",
        "user-agent" -> "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36")

这里的诀窍是DELETE e.* FROM employee_salary e WHERE e.emp_id IN (SELECT emp_id FROM (SELECT emp_id FROM employee_salary GROUP BY emp_id, project, salary HAVING COUNT(*) > 1) x);上的子查询将强制MySQL创建一个临时表，该表独立于x上发生的删除。

Answer 2

试试这个：

Delete from employee_salary
where emp_id in(
         select * from (
          select emp_id from
          employee_salary 
          group by emp_id,project,salary 
          having count(*)>1 ) 
        as alias
)

我正在更改结果集的名称，以便它可以正常工作。

ERROR 1093（HY000）：您无法指定目标表＆＃39; employee_salary＆＃39;用于FROM子句

2 个答案: