如何找到所有具有引用特定 table.column 的外键并具有这些外键值的表？

干得好：

USE information_schema;
SELECT *
FROM
  KEY_COLUMN_USAGE
WHERE
  REFERENCED_TABLE_NAME = 'X'
  AND REFERENCED_COLUMN_NAME = 'X_id';

如果您有多个具有相似表/列名称的数据库，您可能还希望将查询限制为特定数据库：

SELECT *
FROM
  KEY_COLUMN_USAGE
WHERE
  REFERENCED_TABLE_NAME = 'X'
  AND REFERENCED_COLUMN_NAME = 'X_id'
  AND TABLE_SCHEMA = 'your_database_name';

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MySQL 5.5 参考手册："InnoDB and FOREIGN KEY Constraints"

SELECT
  ke.REFERENCED_TABLE_SCHEMA parentSchema,
  ke.referenced_table_name parentTable,
  ke.REFERENCED_COLUMN_NAME parentColumnName,
  ke.TABLE_SCHEMA ChildSchema,
  ke.table_name childTable,
  ke.COLUMN_NAME ChildColumnName
FROM
  information_schema.KEY_COLUMN_USAGE ke
WHERE
  ke.referenced_table_name IS NOT NULL
  AND ke.REFERENCED_COLUMN_NAME = 'ci_id' ## Find Foreign Keys linked to this Primary Key
ORDER BY
  ke.referenced_table_name;

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此解决方案不仅会显示所有关系，还会显示约束名称，这在某些情况下是必需的（例如删除约束）：

SELECT
    CONCAT(table_name, '.', column_name) AS 'foreign key',
    CONCAT(referenced_table_name, '.', referenced_column_name) AS 'references',
    constraint_name AS 'constraint name'
FROM
    information_schema.key_column_usage
WHERE
    referenced_table_name IS NOT NULL;

如果要检查特定数据库中的表，请添加以下内容：

AND table_schema = 'database_name';

---

您可以在巧妙命名的 information_schema 表中找到所有架构相关信息。

您可能需要检查表 REFERENTIAL_CONSTRAINTS 和 KEY_COLUMN_USAGE。前者告诉你哪些表被其他人引用；后者会告诉你他们的领域是如何相关的。

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列出数据库中的所有外键，包括描述

    SELECT  
    i1.CONSTRAINT_NAME, i1.TABLE_NAME,i1.COLUMN_NAME,
    i1.REFERENCED_TABLE_SCHEMA,i1.REFERENCED_TABLE_NAME, i1.REFERENCED_COLUMN_NAME,
    i2.UPDATE_RULE, i2.DELETE_RULE 
    FROM   
    information_schema.KEY_COLUMN_USAGE AS i1  
    INNER JOIN 
    information_schema.REFERENTIAL_CONSTRAINTS AS i2 
    ON i1.CONSTRAINT_NAME = i2.CONSTRAINT_NAME 
    WHERE i1.REFERENCED_TABLE_NAME IS NOT NULL  
    AND  i1.TABLE_SCHEMA  ='db_name';

限制到表中的特定列

AND i1.table_name = 'target_tb_name' AND i1.column_name = 'target_col_name'

---

我写了一个小 bash onliner，您可以将其写入脚本以获得友好的输出：

mysql_references_to：

mysql -uUSER -pPASS -A DB_NAME -se "USE information_schema; SELECT * FROM KEY_COLUMN_USAGE WHERE REFERENCED_TABLE_NAME = '$1' AND REFERENCED_COLUMN_NAME = 'id'\G" | sed 's/^[ \t]*//;s/[ \t]*$//' |egrep "\<TABLE_NAME|\<COLUMN_NAME" |sed 's/TABLE_NAME: /./g' |sed 's/COLUMN_NAME: //g' | paste -sd "," -| tr '.' '\n' |sed 's/,$//' |sed 's/,/./'

所以执行：mysql_references_to transaccion（其中 transaccion 是一个随机表名）给出如下输出：

carrito_transaccion.transaccion_id
comanda_detalle.transaccion_id
comanda_detalle_devolucion.transaccion_positiva_id
comanda_detalle_devolucion.transaccion_negativa_id
comanda_transaccion.transaccion_id
cuenta_operacion.transaccion_id
...

---

SELECT TABLE_NAME, COLUMN_NAME FROM information_schema.KEY_COLUMN_USAGE WHERE CONSTRAINT_SCHEMA LIKE 'your_database' AND TABLE_SCHEMA LIKE 'your_database' AND REFERENCED_TABLE_SCHEMA LIKE 'your_database' AND REFERENCED_TABLE_NAME LIKE 'your_table' AND REFERENCED_COLUMN_NAME LIKE 'your_column';

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06 2022

基于@Panayotis 的回答，但结构更好。

这将列出来自多个表的所有约束。
我也包含了 TABLE_SCHEMA 以显示数据库名称。

SQL

SELECT
    TABLE_SCHEMA AS 'Database',
    TABLE_NAME AS t1,
    REFERENCED_TABLE_NAME AS 't2 (reference table)',
    COLUMN_NAME AS 't1 column',
    REFERENCED_COLUMN_NAME AS 't2 column (reference table)',
    CONSTRAINT_NAME AS 't1 (constrain name)'
FROM
    information_schema.key_column_usage
WHERE
    referenced_table_name IS NOT NULL

输出

+------------+------------+---------------------+---------------+----------------------------+------------------------+
| Database   | t1         | t2 (reference table) | t1 column     | t2 column (reference table) | t1 (constrain name)    |
+============+============+=====================+===============+============================+========================+
| foobar     | credential | userdetail          | userdetail_fk | id                         | credentialUserdetailFk |
+------------+------------+---------------------+---------------+----------------------------+------------------------+
| foobar     | loginlog   | userdetail          | userdetail_fk | id                         | loginlogUserdetailFk   |
+------------+------------+---------------------+---------------+----------------------------+------------------------+
+ client     | userdetail | client              | client_fk     | id                         | userdetailClientFk     |
+------------+------------+---------------------+---------------+----------------------------+------------------------+

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最简单： 1. 打开 phpMyAdmin 2. 在左侧单击数据库名称 3. 在右上角找到“设计器”选项卡

所有约束都将显示在那里。

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