USE `test_db`;

DROP TABLE IF EXISTS tmp_migrate_table_record;
CREATE TABLE tmp_migrate_table_record(
    `id` INT PRIMARY KEY NOT NULL AUTO_INCREMENT COMMENT '主鍵ID',
    `table_name` VARCHAR(50) COMMENT '遷移表名',
    `source_table_count` INT COMMENT '源表記錄數(shù)',
    `target_table_count` INT COMMENT '源表記錄數(shù)',
    `max_id` BIGINT COMMENT '已遷移最大主鍵id'
);

DROP PROCEDURE IF EXISTS p_migrate_full_table_data;
DELIMITER $$
CREATE PROCEDURE p_migrate_full_table_data(IN sourceSchema VARCHAR(50), IN tableName VARCHAR(50), IN primaryKey VARCHAR(50), IN batchSize INT)
BEGIN    
    -- 判斷舊表是否存在，若存在則刪除舊表（強(qiáng)制重新建表）
    SET @dropTableSql = CONCAT('DROP TABLE IF EXISTS ', tableName, ';');
    PREPARE dropTableSql FROM @dropTableSql;
    EXECUTE dropTableSql;
    
    -- 依賴源數(shù)據(jù)，創(chuàng)建新表（這里可以根據(jù)需要更換表名）
    SET @craeteTable = CONCAT('CREATE TABLE ', tableName, ' LIKE `', sourceSchema, '`.', tableName, ';');
    PREPARE craeteTable FROM @craeteTable;
    EXECUTE craeteTable;

    -- 清除當(dāng)前表遷移數(shù)據(jù)記錄數(shù)，防止有舊數(shù)據(jù)影響
    SET @deleteCountSql = CONCAT('DELETE FROM tmp_migrate_table_record WHERE table_name=''', tableName, ''';');
    PREPARE deleteCountSql FROM @deleteCountSql;
    EXECUTE deleteCountSql;
    
    -- 初始記錄臨時(shí)表正在進(jìn)行數(shù)據(jù)遷移的表信息
    SET @countSql = CONCAT('INSERT INTO tmp_migrate_table_record(table_name, source_table_count, target_table_count) SELECT ''', tableName, ''', COUNT(*), 0 FROM `', sourceSchema, '`.', tableName, ';');
    PREPARE countSql FROM @countSql;
    EXECUTE countSql;
    
    -- 用于查看預(yù)編譯后的SQL腳本，若有需要可以打開注釋查看
    -- SELECT @dropTableSql, @craeteTable, @deleteCountSql, @countSql;
    
    -- 數(shù)據(jù)源表記錄數(shù)
    SET @sourceCount = 0;
    -- 目標(biāo)表記錄數(shù)
    SET @targetCount = 0;
    -- 已導(dǎo)入最大id
    SET @maxId = 0;
    
    SELECT source_table_count, target_table_count, IFNULL(max_id, 0) INTO @sourceCount, @targetCount, @maxId FROM tmp_migrate_table_record WHERE table_name=tableName;
    
    -- 循環(huán)分批遷移數(shù)據(jù)，根據(jù)已遷移數(shù)量與需要遷移數(shù)量進(jìn)行比較
    WHILE @sourceCount <> @targetCount DO
        -- 開啟事務(wù)
        START TRANSACTION;
        
        -- 執(zhí)行數(shù)據(jù)分批遷移
        SET @insertSql = CONCAT('INSERT INTO ', tableName, ' SELECT * FROM `', sourceSchema, '`.', tableName, ' WHERE ', primaryKey, ' > ', @maxId, ' ORDER BY ', primaryKey, ' ASC ', 'LIMIT ', batchSize, ';');
        PREPARE insertSql FROM @insertSql;
        EXECUTE insertSql;
        
        -- 實(shí)時(shí)更新臨時(shí)表已遷移記錄數(shù)
        SET @updateCountSql = CONCAT('UPDATE tmp_migrate_table_record SET target_table_count = (SELECT COUNT(*) FROM ', tableName, ') WHERE table_name=''', tableName, ''';');
        PREPARE updateCountSql FROM @updateCountSql;
        EXECUTE updateCountSql;
        
        -- 跟新臨時(shí)表以遷移數(shù)據(jù)最大主鍵id
        SET @updateMaxIdSql = CONCAT('UPDATE tmp_migrate_table_record SET max_id = (SELECT IFNULL(MAX(', primaryKey,'), 0) FROM ', tableName, ') WHERE table_name=''', tableName, ''';');
        PREPARE updateMaxIdSql FROM @updateMaxIdSql;
        EXECUTE updateMaxIdSql;
        
        -- 刷新變量
        SELECT target_table_count, max_id INTO @targetCount, @maxId FROM tmp_migrate_table_record WHERE table_name=tableName;
        
        -- 查看上面拼裝后的sql，需要排查問題可打開查看
        SELECT @insertSql, @updateCountSql, @updateMaxIdSql, @sourceCount, @targetCount;
        
        -- 提交事務(wù)
        COMMIT;
    END WHILE;
END $$
DELIMITER ;

DROP TABLE IF EXISTS tmp_migrate_table_record;

DROP TABLE IF EXISTS t_student;
CREATE TABLE t_student(
    id BIGINT,
    `name` VARCHAR(50),
    age INT(3),
    state CHAR(1),
    PRIMARY KEY (id)
);

DROP TABLE IF EXISTS t_course;
CREATE TABLE t_course(
    id BIGINT,
    `name` VARCHAR(50)
);

DROP PROCEDURE IF EXISTS init_student;
DELIMITER $$
CREATE PROCEDURE init_student()
BEGIN
    DELETE FROM t_student;
    SET @p = 1;
        -- 測(cè)試數(shù)據(jù)數(shù)量自己定
    WHILE @p < 234567 DO
        INSERT INTO t_student
        VALUES(@p, CONCAT('user', @p * 1000000), 18, 'A');
        SET @p = @p + 1;
    END WHILE;
END $$
DELIMITER ;

CALL init_student();

CALL p_migrate_full_table_data('test_source_db', 't_student', 'id', 50000);
CALL p_migrate_full_table_data('test_source_db', 't_course', 'id', 50000);