mysql判断表是不是存在

Posted 2023-03-23

SELECT count( * )
FROM information_schema.TABLES
WHERE table_name = 'table name'
AND TABLE_SCHEMA = 'database name' 参考技术A SHOW TABLES LIKE '%表名%';

Mysql判断表字段或索引是不是存在

参考技术A 判断字段是否存在：
DROP
PROCEDURE
IF
EXISTS
schema_change;
DELIMITER
//
CREATE
PROCEDURE
schema_change()
BEGIN
DECLARE
CurrentDatabase
VARCHAR();
SELECT
DATABASE()
INTO
CurrentDatabase;
IF
NOT
EXISTS
(SELECT
*
FROM
information_schema.columns
WHERE
table_schema=CurrentDatabase
AND
table_name
=
'rtc_order'
AND
column_name
=
'IfUpSend')
THEN
ALTER
TABLE
rtc_order
ADD
COLUMN
`IfUpSend`
BIT
NOT
NULL
DEFAULT
COMMENT
'是否上传
是否上传';
END
IF;
END//
DELIMITER
;
CALL
schema_change();
判断索引是否存在：
DROP
PROCEDURE
IF
EXISTS
schema_change;
DELIMITER
//
CREATE
PROCEDURE
schema_change()
BEGIN
DECLARE
CurrentDatabase
VARCHAR();
SELECT
DATABASE()
INTO
CurrentDatabase;
IF
NOT
EXISTS
(SELECT
*
FROM
information_schema.statistics
WHERE
table_schema=CurrentDatabase
AND
table_name
=
'rtc_phototype'
AND
index_name
=
'index_name')
THEN
ALTER
TABLE
`rtc_Phototype`
ADD
INDEX
index_name
(
`imgtype`
);
END
IF;
END//
DELIMITER
;
CALL
schema_change();
从这两段可以看出很多东西，具体可以自己试验一下
关于小编给大家介绍的Mysql判断表字段或索引是否存在的内容就给大家介绍到这里，希望对大家有所帮助！