多个INNER JOIN SQL ACCESS

Question

查询表达式中的语法错误（缺少运算符），“tbl_employee.emp_id = tbl_netpay.emp_id INNER JOIN tbl_gross ON tbl_employee.emp_id = tbl_gross.emp_ID INNER JOIN tbl_tax ON tbl_employee.emp_id - tbl_tax.emp_ID”。

SELECT tbl_employee.emp_ID,
tbl_employee.emp_name,
tbl_gross.BasicSalary,
tbl_gross.totalOT,
tbl_netpay.totalGross,
tbl_tax.totalLate,
tbl_tax.allowance,
tbl_tax.SSS,
tbl_tax.PhilHealth,
tbl_tax.GSIS,
tbl_tax.HDMF,
tbl_netpay.totalDeduc,
tbl_netpay.emp_ti,
tbl_netpay.emp_wt,
tbl_netpay.emp_np
FROM  tbl_employee
INNER JOIN tbl_netpay ON tbl_employee.emp_id = tbl_netpay.emp_id
INNER JOIN tbl_gross ON tbl_employee.emp_id = tbl_gross.emp_ID
INNER JOIN tbl_tax ON tbl_employee.emp_id = tbl_tax.emp_ID;

我总是会遇到上述错误。

- emerjohn12

Answer 1

如果查询包含多个连接，请在FROM子句中使用圆括号。尝试以下方式...

FROM
    ((tbl_employee
    INNER JOIN tbl_netpay
    ON tbl_employee.emp_id = tbl_netpay.emp_id)
    INNER JOIN tbl_gross
    ON tbl_employee.emp_id = tbl_gross.emp_ID)
    INNER JOIN tbl_tax
    ON tbl_employee.emp_id = tbl_tax.emp_ID;

如果可能的话，请使用Access查询设计器来设置连接。设计器将根据需要添加括号，以使数据库引擎保持良好状态。

- HansUp

Answer 2

感谢HansUp的回答，非常有帮助且有效！

我在Access中找到了三种模式，你的是最好的，因为它适用于所有情况。

• INNER JOIN, your variant. I will call it "closed set pattern". It is possible to join more than two tables to the same table with good performance only with this pattern.

  SELECT C_Name, cr.P_FirstName+" "+cr.P_SurName AS ClassRepresentativ, cr2.P_FirstName+" "+cr2.P_SurName AS ClassRepresentativ2nd
  FROM
       ((class
         INNER JOIN person AS cr 
         ON class.C_P_ClassRep=cr.P_Nr
       )
       INNER JOIN person AS cr2
       ON class.C_P_ClassRep2nd=cr2.P_Nr
    )
  

  ;

• INNER JOIN "chained-set pattern"

  SELECT C_Name, cr.P_FirstName+" "+cr.P_SurName AS ClassRepresentativ, cr2.P_FirstName+" "+cr2.P_SurName AS ClassRepresentativ2nd
  FROM person AS cr
  INNER JOIN ( class 
     INNER JOIN ( person AS cr2
     ) ON class.C_P_ClassRep2nd=cr2.P_Nr
  ) ON class.C_P_ClassRep=cr.P_Nr
  ;
  

• CROSS JOIN with WHERE

  SELECT C_Name, cr.P_FirstName+" "+cr.P_SurName AS ClassRepresentativ, cr2.P_FirstName+" "+cr2.P_SurName AS ClassRepresentativ2nd
  FROM class, person AS cr, person AS cr2
  WHERE class.C_P_ClassRep=cr.P_Nr AND class.C_P_ClassRep2nd=cr2.P_Nr
  ;
  

- michbau