MySQL determines whether a table field or index exists, and then modifies

To determine whether a field exists:

1 DROP PROCEDURE IF EXISTSSchema_change; 2DELIMITER//3 CREATE PROCEDURESchema_change ()BEGIN 4 DECLARECurrentDatabaseVARCHAR( -);5 SELECT DATABASE() intocurrentdatabase;6 IF  not EXISTS(SELECT *  fromInformation_schema.columnsWHERETable_schema=CurrentDatabase andtable_name= 'Rtc_order'  andcolumn_name= 'Ifupsend') Then  7     ALTER TABLERtc_order8     ADD COLUMN' Ifupsend 'BIT   not NULL  DEFAULT 0COMMENT' upload or not upload';9 END IF; Ten END//   One DELIMITER;  ACall Schema_change ();

Determine if the index exists:

1 DROP PROCEDURE IF EXISTSSchema_change; 2DELIMITER//3 CREATE PROCEDURESchema_change ()BEGIN 4 DECLARECurrentDatabaseVARCHAR( -);5 SELECT DATABASE() intocurrentdatabase;6 IF  not EXISTS(SELECT *  fromInformation_schema.Statistics WHERETable_schema=CurrentDatabase andtable_name= 'Rtc_phototype'  andIndex_name= 'index_name') Then  7    ALTER TABLE' Rtc_phototype 'ADD INDEXindex_name (' Imgtype ');8 END IF; 9 END//  Ten DELIMITER;  OneCall Schema_change ();

MySQL determines whether a table field or index exists, and then modifies