用defs函数，例如查ops模块用下列语句：
select * from defs() where name like "ops::%"
返回结果:
name isCommand userDefined minParamCount maxParamCount syntax ops::cancelJobEx false true 0 1 (id) ops::checkChunkReplicas false true 3 3 (dbPath,tableName,targetChunkId) ops::checkOLAPChunkReplicas false true 3 3 (dbName,tableName,targetChunkId) ops::checkTSDBChunkReplicas false true 3 3 (dbName,tableName,targetChunkId) ops::closeInactiveSessions false true 0 1 (hours) ops::dropRecoveringPartitions false true 1 2 (dbPath,tableName) ops::gatherClusterPerf false true 0 3 (monitoringPeriod,scrapeInterval,dir) ops::gatherStreamingStat false true 1 4 (subNode,monitoringPeriod,scrapeInterval,dir) ops::getAllLicenses false true 0 0 () ops::getDDL false true 2 2 (database,tableName) ops::getDifferentData false true 2 2 (t1,t2) ops::getTableDiskUsage false true 2 3 (database,tableName,byNode) ops::unsubscribeAll false true 0 0 () ops::updateAllLicenses false true 0 0 ()
注意：ops模块是dolphindb server预安装的模块，use ops之后即能使用。