Oracle query statement summary

// Query the record with a certain field as a certain value
select * from sales where type = ' wallet '

// Fuzzy query
select * from sys_users where name like '% Wu %'

// Go to check again
select distinct type_name, table_name from menuTab;

// Before query 10 strip
select * caseTab where rownum < 10;

// Count the number of different values in a field
select count(distinct(caseType)) from caseTab;

// Count the number of different values in a field
select caseType, count(1) from caseTab group by caseType;

// Left join
select * from caseTab a left join caseTypeTab b on a.id = b.id  where  caseDt between to_date('2020-07-01 00:00:00','yyyy-mm-dd hh24:mi:ss') and to_date('2020-07-31 00:00:00','yyyy-mm-dd hh24:mi:ss')
// Right join
// And left join similar , The difference lies in the left join Keep all records in the table on the left , Even if there's no match on Items in the condition *** Be careful , The condition here refers to on hinder                   // And right join Keep the records of the table on the right