Question

我需要一个查询（INFORMATION_SCHEMA），它将为给定的架构和表名显示所有具有以下属性的表列（它是什么键类型：PK =＆gt;主键，UQ =＆gt;唯一键，FK =＆gt; ;外键，什么是键名，如果是外键，则引用schema.table.column）：

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这是我的SQL：

Sub INeedaDate()
   Dim r As Range
   For Each r In Selection
      v = r.Text
      r.Value = DateSerial(Left(v, 4), Mid(v, 5, 2), Right(v, 2))
      r.NumberFormat = "mm/dd/yyyy"
   Next r
End Sub

以下是我的表：

COLUMN_NAME | DATA_TYPE | KEY_TYPE | KEY_NAME    | REFERENCED
============+===========+==========+=============+========================
empid       | int       | PK       | PRIMARY     |
empname     | varchar   | UQ       | uq_empname  |
empactive   | enum      |          |             |
empcatid    | int       | FK       | fk_emp_cat  | schema.categories.catid

Answer 1

这是我的最后一个（透视）查询：

SELECT c.COLUMN_NAME,
       --c.COLUMN_KEY,
       IF(EXISTS(select *
                 FROM information_schema.KEY_COLUMN_USAGE k
                 JOIN information_schema.TABLE_CONSTRAINTS tc 
                   ON (k.TABLE_SCHEMA=tc.TABLE_SCHEMA 
                       AND k.TABLE_NAME=tc.TABLE_NAME 
                       AND k.CONSTRAINT_NAME=tc.CONSTRAINT_NAME)
                WHERE k.TABLE_SCHEMA=c.TABLE_SCHEMA 
                      AND k.TABLE_NAME=c.TABLE_NAME 
                      AND tc.CONSTRAINT_TYPE='PRIMARY KEY' 
                      AND c.COLUMN_NAME=k.COLUMN_NAME),'PK',null) AS PK,
       IF(EXISTS(select *
                 FROM information_schema.KEY_COLUMN_USAGE k
                 JOIN information_schema.TABLE_CONSTRAINTS tc 
                   ON (k.TABLE_SCHEMA=tc.TABLE_SCHEMA 
                      AND k.TABLE_NAME=tc.TABLE_NAME 
                      AND k.CONSTRAINT_NAME=tc.CONSTRAINT_NAME)
                WHERE k.TABLE_SCHEMA=c.TABLE_SCHEMA 
                      AND k.TABLE_NAME=c.TABLE_NAME 
                      AND tc.CONSTRAINT_TYPE='UNIQUE' 
                      AND c.COLUMN_NAME=k.COLUMN_NAME),'UQ',null) AS UQ,
       IF(EXISTS(select *
                 FROM information_schema.KEY_COLUMN_USAGE k
                 JOIN information_schema.TABLE_CONSTRAINTS tc 
                   ON (k.TABLE_SCHEMA=tc.TABLE_SCHEMA 
                      AND k.TABLE_NAME=tc.TABLE_NAME 
                      AND k.CONSTRAINT_NAME=tc.CONSTRAINT_NAME)
                WHERE k.TABLE_SCHEMA=c.TABLE_SCHEMA 
                      AND k.TABLE_NAME=c.TABLE_NAME 
                      AND tc.CONSTRAINT_TYPE='FOREIGN KEY' 
                      AND c.COLUMN_NAME=k.COLUMN_NAME),'FK',null) AS FK,
       c.EXTRA,
       c.IS_NULLABLE,
       c.DATA_TYPE,
       c.COLUMN_TYPE,
       c.CHARACTER_MAXIMUM_LENGTH,
       c.COLUMN_COMMENT,
       k.REFERENCED_TABLE_SCHEMA,
       k.REFERENCED_TABLE_NAME,
       k.REFERENCED_COLUMN_NAME
FROM information_schema.COLUMNS c
LEFT JOIN information_schema.KEY_COLUMN_USAGE k
    ON (k.TABLE_SCHEMA=c.TABLE_SCHEMA
   AND k.TABLE_NAME=c.TABLE_NAME
   AND k.COLUMN_NAME=c.COLUMN_NAME
   AND k.POSITION_IN_UNIQUE_CONSTRAINT IS NOT NULL)
 WHERE c.TABLE_SCHEMA='PHPDAO'
   AND c.TABLE_NAME='employees';

但我认为必须有更简单的解决方案。

显示具有键类型和引用的MYSQL表列

1 个答案: