IF EXISTS(SELECT * FROM sys.indexes WHERE object_id = object_id('schema.tablename') AND NAME ='indexname') DROP INDEX indexname ON SCHEMA.tablename; CREATE INDEX indexname ON SCHEMA.tablename(columnlist); Why no
That's the code generated in SchemaModifier: create unique index if not exists index_client_ref on [...] And this is the exception i'm getting: io.requery.PersistenceException: java.sql.SQLSyntaxErrorException: You have an error in your ...
IF EXISTS(SELECT * FROM sys.indexes WHERE object_id = object_id('schema.tablename') AND NAME ='indexname') DROP INDEX indexname ON SCHEMA.tablename; CREATE INDEX indexname ON SCHEMA.tablename(columnlist); Why not simply: Create Index IndexName on schema.tablename (columnlist) with (drop...
The Database Engine doesn't allow creating a unique index on columns that already include duplicate values, whether or not IGNORE_DUP_KEY is set to ON. If this is attempted, the Database Engine displays an error message. Duplicate values must be removed before a unique index can be created...
已排序的叢集數據行存放區索引是在 SQL Server 2022 (16.x) 中引進的。 如需詳細資訊,請參閱 CREATE COLUMNSTORE INDEX。 如需了解有序的資料行存放庫索引的可用性,請參閱 資料行存放庫索引:概觀。 從SQL Server 2016 (13.x) 開始,您可以將資料表建立為叢集數據行存放區索引。 您不再需要先建立數...
DEGREES (SQL Server Compact) DELETE (SQL Server Compact) DML Statements (SQL Server Compact) DROP INDEX (SQL Server Compact) DROP STATISTICS (SQL Server Compact) DROP TABLE (SQL Server Compact) EXISTS (SQL Server Compact) EXP (SQL Server Compact) Expressions (SQL Server Compact) FLOOR (SQL ...
十三、sql server not exists exists : 强调的是是否返回结果集,不要求知道返回什么, 比如: select name from student where sex = 'm' and mark exists(select 1 from grade where ...) ,只要 exists引导的子句有结果集返回,那么exists这个条件就算成立了,大家注意返回的字段始终为1,如果改成“select 2 from...
To create a unique index on a table, using: SQL Server Management Studio Transact-SQL Before You Begin Benefits of a Unique Index Multicolumn unique indexes guarantee that each combination of values in the index key is unique. For example, if a unique index is created on a combination ofLas...
[ NULL | NOT NULL ] { PRIMARY KEY | UNIQUE } [ CLUSTERED | NONCLUSTERED ] [ WITH FILLFACTOR = fillfactor | WITH ( <index_option> [ , ...n ] ) [ ON { filegroup | "default" } ] ] | [ CHECK ( logical_expression ) ] [ , ...n ] } <computed_column_definition> ::= ...
If an XML index exists, the clustered, primary key of the table can't be modified. You'll have to drop all XML indexes on the table before modifying the primary key. A primary XML index can be created on a single xml type column. You can't create any other type of index with the...