Select items from a list based on alphabetical order criteria Why are there no advanced computers in an advanced society Why did the number of Germans in Kazakhstan start to increase Suppose that I have two select statements: select foo,bar from baz as b, select foo, bar,gee,whiz from qaz as q Suppose the second select statement has a join: select foo, bar, gee, whiz from qaz as q. left join data like d on d.gee, q.gee where d.whiz, q.whiz. and q.foo is not NULL. Now how can I combine these two separate selects into one, The syntax of a SQL JOIN is: SELECT FROM table1. JOIN table2. ON table1.id1 table2.id2. Since this is a SQL JOINs tutorial aimed at beginners, let's start with the basics. We will review the items. So, for example, if a product is obsolete but you don't know if the product is in stock, you don't know if the product is salable. You can write this three-value logic as follows: SELECT CASE. WHEN obsolete, NOR in stock, WHEN true. WHEN NOT obsolete, NOR in stock, O, THEN false. OTHER POINT. END AS salable.The salary level is determined in the SELECT statement itself, by applying an SQL if statement in the SELECT logic, categorizing salaries into Grade C, Grade B, and Grade A based on the specified salary ranges. 2. CHOOSE Function. The CHOOSE function simplifies conditional logic by acting like a search. The best way is to have a static calendar table, otherwise you can generate a set of dates on the fly as follows: SELECT TOP DATEDIFF DAY, StartDate, EndDate, 1 Date, DATEADD DAY, ROW NUMBER, OVERORD BY a. object id - 1, StartDate FROM sys.all objects a. CROSS JOIN sys.all objects bDataTable dt, new DataTable, da.Fill dt, returns dt. if you want to use DataSet instead of DataTable, replace where I have DataTable with or change the method to return a DataSet like this below. public DataSet GetData string sqlcmdString, string connString SqlConnection con, new SqlConnection connStringSQL administrators typically use subqueries inside the WHERE clause to refine the result of the main query or outer query. You usually enclose subqueries in parentheses, and you can use them with comparison operators like lt gt lt and gt. A valid use case for a subquery is to use it with the SELECT statement when you don't. After executing update from a select statement, the table result will be as below 1. SELECT, FROM Persons. As we can see, the data in the PersonCityName column of the Persons table has been updated with the data in the City column of the AddressList table for the matching records in the PersonId column. The easiest way to implement myself is to first take the value I need. just to make a separate selection like. SELECT IntKey FROM Currency WHERE Text, param. then run it, take the value and use it in my INSERT, but I would like to combine it into a single query if possible. I tried this: SQL admins usually use subqueries inside the WHERE clause to narrow down the result of the main query or outer query. . You usually enclose subqueries in parentheses and you can use them with, SELECT value table EXISTS, SELECT theValue from theValues ​​​​WHERE theValue, 2 UNION ALL. SELECT value table EXISTS, SELECT theValue from theValues ​​​​WHERE theValue, 2 In this case the magic number If theValues ​​table is queried, then you get the