easy sql query builder

1. The basic query statement is followed by a WHERE 1=1 to facilitate the query condition.ASKSTR: = ' select * from twork where 1=1 ', if Length (Cxteworkid.text) 　　2. Multiple-table queries can replace a table with a single string. Logically clearer.worktable = ' Select Gworkid from twork where 1=1 '; paytable = ' select sum (gxmtotal) as Sgxmtotal,gxmtype from Tpay where Gworkid in '; Paygroupby = ' Group

Original: SQL statement tip: Query for data records that exist in one table and not in anotherMethod One (only for single fields)Easy to understand, low efficiency with not inSelect a.ID from A where a.id not in (select ID from B)Method Two (for multiple field matches)Use left Join...on ..., "b.ID isnull" indicates a record in which the b.ID field is null after t

as average age 2 from student 3Group by Gradeid 3--inquiry for students in each grade including Beijing 1 Select Gradeid,COUNT(1 as total number 2 from student 3 where like ' % BEIJING% ' 4 Group by Gradeid 4--for students who have taken the exam, the average number of students who have passed the test (student, average), in descending order 1 SelectStudentno,AVG(Studentresult) asAverage score2 fromResult3 Group byStudentno4 having AVG(Studentresult)>= - 5 Order byAverag