--1.建立索引資訊表
create table `t_index_update` (
`table_name` varchar(20) collate gbk_bin default null,
`index_name` varchar(20) collate gbk_bin default null,
`index_cols` varchar(100) collate gbk_bin default null
) engine=innodb default charset=gbk collate=gbk_bin;
--2.插入線下索引資訊表
insert into t_index_update()
select
table_name,
index_name,
group_concat(distinct concat('`', column_name, '`') order by seq_in_index asc separator ', ') as index_cols
from information_schema.statistics
where table_schema= 'elk'
and column_name<>'seq_id'
and index_name<>'primary'
group by table_name, index_name
order by table_name asc, index_name asc;
--3.同步線下索引資訊表到線上
--4.構建刪除和修改過的索引的刪除語句
select concat('alter table `',a.table_name,'` drop index ',a.index_name,';')
from
select
table_name,
index_name,
group_concat(distinct concat('`', column_name, '`') order by seq_in_index asc separator ', ') as index_cols
from information_schema.statistics
where table_schema= 'elk'
and column_name<>'seq_id'
and index_name<>'primary'
group by table_name, index_name
) aleft join t_index_update b on b.table_name and b.index_name=a.index_name and b.index_cols=a.index_cols
where b.index_name is null;
--5.構建新加索引的的新加語句
select concat('alter table `',a.table_name,'` add index ',a.index_name,'(',a.index_cols,');')
from t_index_update a
left join (
select
table_name,
index_name,
group_concat(distinct concat('`', column_name, '`') order by seq_in_index asc separator ', ') as index_cols
from information_schema.statistics
where table_schema= 'elk'
and column_name<>'seq_id'
and index_name<>'primary'
group by table_name, index_name
) b on b.table_name and b.index_name=a.index_name and b.index_cols=a.index_cols
where b.index_name is null;
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