SQL Server calculates a part of the time difference function "Go"

The DateDiff () function and the GETDATE () function are needed when you are doing SQL Server development and sometimes need to get the data in the table today, yesterday, this week, last week, this month, and last month.
DATEDIFF (DatePart, StartDate, EndDate)
Explanation: Calculating the time difference
Datepare Value: Year | Quarter | Month | Week | Day | Hour | Minute | Second | Millisecond
StartDate: Start date
EndDate: End Date
GetDate ()
Explanation: Get the current system date

In the following example, the table name is TableName and the condition field is named Inputdate
Query today

SELECT * FROM TableName where DATEDIFF (Day,inputdate,getdate ()) =0
Query yesterday

SELECT * FROM TableName where DATEDIFF (Day,inputdate,getdate ()) =1
Query this week

SELECT * FROM TableName where DATEDIFF (Week,inputdate,getdate ()) =0
Query last week

SELECT * FROM TableName where DATEDIFF (Week,inputdate,getdate ()) =1
Check this month

SELECT * FROM TableName where DATEDIFF (Month,inputdate,getdate ()) =0
Query last month

SELECT * FROM TableName where DATEDIFF (Month,inputdate,getdate ()) =1

Reprint Address: http://www.devdo.net/sql-server-query-date.html

Merge two tables simultaneously query

For example:

Table A has field ID name age

Table B has field ID sex address

Query Sql:select * FROM (select Id,name,age,null sex,null address from a UNION ALL select Id,null name,null age,sex,address From B)

Principle: Let two tables have the same field name, null sex==null as sex, because the a table has no sex column, so we define a null column. This will have the same column as the B table.

UNION ALL is a query for all data displayed for two tables.

SQL Server calculates a part of the time difference function "Go"