sql select 1 if exists

1 determining whether a database existsSQL codeif exists (SELECT * from sys.databases WHERE name = ' database name ')drop database [DB name] if exists (SELECT * from sys.databases WHERE name = ' database name ')drop database [DB name]2 Determining

--whether the database existsIF exists(SELECT * fromMaster.. sysdatabasesWHEREName=N'Library name')PRINT 'exists'ELSE PRINT 'Not exists'-----------------determine if the name of the table to be created existsIF exists(SELECT *

Summary:Exists (the result set returned by SQL is true) not exists (the result set returned by SQL is true) is as follows: Table A ID name 1 A1 2 A2 Exists (the result set returned by SQL is true)Not exists (SQL does not return true result sets)As

--查看对象是否已经存在  --数据库是否存在   --if exists (select * from sys.databases where name = ’数据库名’)    --  drop database [数据库名]      if exists(select * from sys.databases where name=‘FGM_POS‘)  print ‘存在‘--drop database [数据库名]   --表是否存在   --if exists (select *

Use if exists to build a table "go"1 Determine if the database has SQL codeif exists (SELECT * from sys.databases WHERE name = ' database name ')drop database [DB name] if exists (SELECT * from sys.databases WHERE name = ' database name ')drop

SQL query in the in, exists, not in, not exists usage and difference, sqlexists 1. in and exists In connects the External table to the internal table as a hash (Dictionary set), while exists loops the External table and queries the internal table

Usage and difference of in, exists, not in, and not exists in SQL queries 1. in and exists In connects the External table to the internal table as a hash (Dictionary set), while exists loops the External table and queries the internal table after

Transferred from Https://www.cnblogs.com/liyasong/p/sql_in_exists.html and http://blog.csdn.net/lick4050312/article/details/4476333Table ShowThe two tables involved in the query, a user and an order table, are the following:User table:　　　　Order

For example, there is a query in the Northwind database thatSELECT C.customerid,companyname from Customers CWHERE EXISTS (SELECT OrderID from Orders o WHERE o.customerid=c.customerid)How does this exists work? The subquery returns the OrderID field,

exists summary of database SQL statements SQL exists in learningFirst to compare the following syntax:--deals= Trading tables, areas= regional tables, such as Hong Kong; Our purpose: To view the regions with transactionsSELECT * from areas where ID