Query 2: SELECT * FROM tablename WHERE b = 145. You could add an index on B for this second query. So you'd have 2 indexes, (a,b) and (b). But indexes take place, they take time to update, etc. So in this case, perhaps you'd be better off with a single index that coul...
MySQL 8.0 delivers support for indexes in descending order. Values in such an index are arranged in descending order, and we scan it forward. Before 8.0, when a user create a descending index, we created an ascending index and scanned it backwards. One benefit is that forward index scans ar...
The destination database MySQL 8.0.27 does not support collation rules on full-text indexes. In the source database MariaDB 10.5.8, the DDL statement create table t1(id INT, c1 VARCHAR(32)) ENGINE = INNODB DEFAULT CHARSET = utf8mb4 COLLATE = utf8mb4_nopad_bin is executed to create ...
Indexes are ordered based on their keys. Loose index scan effectively jumps from one unique value (or set of values) to the next based on the index’s prefix keys. In the above query column “c1” is the prefix of the index “c1_c2_idx”. Loose index scan jumps to the unique values...
The MySQL Database Server is very fast, reliable, scalable, and easy to use. If that is what you are looking for, you should give it a try. MySQL Server can run comfortably on a desktop or laptop, alongside your other applications, web servers, and so on, requiring little or no atten...
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Add basic support for hierarchyid type in SQL Server. SSMA v8.2 The v8.2 release of SSMA for MySQL is enhanced with a targeted set of fixes designed to improve quality and conversion metrics, and fixes for: An issue with disabled nonclustered indexes after data migration. Detection of .NET ...
What are ENUMs used for in MySQL? Using Enum can restrict the number of values that can be allowed to go inside a table. If there is an ENUM for Colors ENUM(‘blue’,’yellow’,’green’) I can use an insert statement like Insert colors values (‘red’). ...
cardinality at first. I think place the field with bigger cardinality at first, the index can be used for both "where a = x and b = y" and "where b = x and a = y". However, as for the only one query "where a = x and b = y", the two indexes are the same on ...