`hire_date` dateNOTNULL,PRIMARYKEY(`emp_no`),KEY`idx_first_last` (`first_name`,`last_name`) USING BTREE ) ENGINE=InnoDBDEFAULTCHARSET=utf8; mysql>explainselect*fromemployeeswherefirst_name='Tomofumi'andlast_name='Asmuth';+---+---+---+---+---+---+---+---+---+---+|id|se...
EXPLAINSELECT*FROM`sys_user`primary、union、union result PRIMARY，主查询。UNION，UNION中第二个语句或...
The secondary databases are readable and can be used to offload read-only workloads, thus freeing up resources for transactional workloads on the primary or placing data closer to your end users. Furthermore, the secondary databases can be in the same region as the primary o...
replicate-between-primary-and-secondary-clusters.md replicate-data-to-kafka.md role-based-access-control.md scale-tidb-using-tiup.md schedule-replicas-by-topology-labels.md schema-object-names.md security-compatibility-with-mysql.md shard-row-id-bits.md sql-logical-optimization.md sql-mode....
According to our text “These components include input devices‚ output devices‚ communications devices‚ primary and secondary storage devices‚ and the central processing unit (CPU).” (Stair‚ Reynolds‚ 2003). An input device is any device that transfers information from ...
Batteries come in all different shapes, sizes, voltages, and capacities (amounts of stored charge or energy). Although they can be made with all sorts of different chemical electrolytes and electrodes, there are really only two main types: primary and secondary.Primary batteriesare ordinary, dispo...
Covers all types of primary (single-use) and secondary (rechargeable) lithium batteries, including lithium-ion. Lithium-Ion Batteries: Advances and Applications by Gianfranco Pistoia. Newnes, 2013. An up-to-date review of consumer and industrial applications. Lithium-ion Batteries: Science and ...
For InnoDB, a secondary index might coverthe selected columns even if the query also selects the primary key becauseInnoDB stores the primary key value with each secondary index. If key is NULL,MySQL found no index to use for executing the query more efficiently. ...
Parasite and host cell culture Toxoplasma gondii type I RH tachyzoites were maintained by serial passage in primary human foreskin fibroblasts (HFFs) in Dulbeccos modified Eagles high glucose medium (DMEM; Gibco 11960-044) with 10% heat- inactivated foetal bovine serum (FBS; Corning 35-011-CV...
const用于用常数值比较PRIMARY KEY或UNIQUE索引的所有部分时。在下面的查询中,tbl_name可以用于const表: 1 2 3 4 SELECT * FROM tbl_name WHERE primary_key=1; SELECT * FROM tbl_name WHERE primary_key_part1=1 AND primary_key_part2=2; 例如: 1 2 3 4 5 6 7 mysql> explain select * from em...