一、简介
获取指令使用方法。
二、示例
tcaplus> help;——————————————————————————– help: show usage of commands, example: "help select;". show: get server status related information. executing "help show;" for details. exit/quit: exit the client. count: print record number in the database. desc: print table field name and type. select: query records from database. insert: insert a new record into database. replace: replace a record into the database. update: update a record in the database. delete: delete record(s) from database. dump: dump records from database. load: load records into the database. setttl: set ttl for a record getttl: get ttl for a record——————————————————————————–tcaplus> help select;——————————————————————————–example: select key1, key2, key3, value1, value2 [into result.csv] from table where key1 = 1 and key2 = "abc" [and -index = 1] [\\P] [\\G]; query records from database, you can specify part of the fields or whole fields (select *), and you can write the result to a file, which can be used by "insert" and "load" for generic table, if the key in where clause is not complete, then it will send "GetByPartkey" for list table, if "-index" is not specified in where clause, then it will send "ListGetAll", otherwise it will send "ListGet" \\P: print time usage in detail \\G: print fields in column Note: "-index" only used for list tableexample: select * [into result.xml] from table where key1 = 1 and key2 = "abc" [and -index = 1] using tdr [\\P]; if you specify "using tdr", then the records will be parsed by tdr file and print in xml format. you can write the result into a file, which can be used by "load" it only support "select *" instead of select part of the fields when specify "using tdr" Note: "-index" only used for list tablegloble index query: example: select * from table where key1 > 1 and value1 > 100; example: select * from table where value1 like "test"; example: select field1, field2 from table where key1 > 1 or value1 > 100; example: select * from table where value1 between 100 and 200; example: select * from table where value1 > 100 limit 100 offset 0; example: select sum(value2), max(value2), min(value2), avg(value2), count(*) from table where value1 > 100; Note: globle index query is only support generic table; Note: current support: =,!=,>,>=,<,<=, like, not like, betwwen, in, not in, and, or, limit offset; Note: current support aggregation: count, sum, max, min, avg; Note: for protobuf table, it support: "select field1.field2 from test where value1 > 100"; Note: limit must be used with offset, lack offset will query failed; Note: the fields in where condition and in aggregation must had already created index; Note: it not support: store the result to a file, such as "select * into file XXX" is not support; Note: it not support: "select * from table"; which means to traverse table, you can used api traverse method to traverse table; Note: it not support: order by, group by, having, join, union and so on; Note: it not support: select a+b XXX; select * from table where a+b>0; select sum(XX),field1 from XXX; select *,field1 from XXX; ……;——————————————————————————–