Dictionary table to find out the table name, column name, data type, field type in the library
SELECT
COLUMN_NAME 列名,
COLUMN_COMMENT field description,
DATA_TYPE data type,
CHARACTER_MAXIMUM_LENGTH length,
IS_NULLABLE AS 'NOT NULL',
column_key index type,
COLUMN_DEFAULT default value
FROM INFORMATION_SCHEMA. COLUMNS
WHERE
table_schema = 'orderdb'
AND
table_name = 'tb_user'
[Table_schema corresponds to the library name, table_name corresponds to the table name]
This statement is very useful when viewing the table structure, especially when writing the table structure, update is 4.10.2020
There is no triplet in the SQL statement -----------: wherea = b = c error
