SQL Server

UPDATE
    Table_A
SET
    Table_A.col1 = Table_B.col1,
    Table_A.col2 = Table_B.col2
FROM
    Some_Table AS Table_A
    INNER JOIN Other_Table AS Table_B
        ON Table_A.id = Table_B.id
WHERE
    Table_A.col3 = 'cool'

SELECT DATEADD(month, DATEDIFF(month, 0, CURRENT_TIMESTAMP), 0)

SELECT COUNT(DISTINCT col1) FROM table1

SELECT col1, COUNT(0) FROM table1 GROUP BY col1

SELECT 
    TABLE_SCHEMA as SchemaName,
    TABLE_NAME as TableName,
    COLUMN_NAME as ColumnName
FROM 
    INFORMATION_SCHEMA.COLUMNS
WHERE 
    COLUMN_NAME LIKE '%<column_name>%';

SELECT
    FK.name AS foreign_key_name,
    FK_TABLE.name AS foreign_key_table,
    FK_COLUMN.name AS foreign_key_column,
    REFERENCED_TABLE.name AS referenced_table,
    REFERENCED_COLUMN.name AS referenced_column
FROM sys.foreign_keys FK
JOIN sys.objects FK_TABLE ON FK_TABLE.object_id = FK.parent_object_id
JOIN sys.objects REFERENCED_TABLE ON REFERENCED_TABLE.object_id = FK.referenced_object_id
JOIN sys.foreign_key_columns FKC ON FKC.constraint_object_id = FK.object_id
JOIN sys.columns FK_COLUMN ON FK_COLUMN.column_id = FKC.parent_column_id AND FK_COLUMN.object_id = FK.parent_object_id
JOIN sys.columns REFERENCED_COLUMN ON REFERENCED_COLUMN.column_id = FKC.referenced_column_id AND REFERENCED_COLUMN.object_id = FK.referenced_object_id
WHERE REFERENCED_TABLE.name = 'Table_Name';

WITH ForeignKeyInfo AS (
    SELECT
        FK.[name] AS ForeignKeyName,
        FK_SCHEMA.[name] AS ForeignKeySchema,
        FK_TABLE.[name] AS ForeignKeyTable,
        FK_COL.[name] AS ForeignKeyColumn,
        REFERENCED_SCHEMA.[name] AS ReferencedSchema,
        REFERENCED_TABLE.[name] AS ReferencedTable,
        REFERENCED_COL.[name] AS ReferencedColumn,
        FKC.constraint_column_id AS ColumnPosition
    FROM sys.foreign_keys FK
    JOIN sys.tables FK_TABLE ON FK_TABLE.object_id = FK.parent_object_id
    JOIN sys.tables REFERENCED_TABLE ON REFERENCED_TABLE.object_id = FK.referenced_object_id
    JOIN sys.schemas FK_SCHEMA ON FK_SCHEMA.schema_id = FK_TABLE.schema_id
    JOIN sys.schemas REFERENCED_SCHEMA ON REFERENCED_SCHEMA.schema_id = REFERENCED_TABLE.schema_id
    JOIN sys.foreign_key_columns FKC ON FK.object_id = FKC.constraint_object_id
    JOIN sys.columns FK_COL ON FK_COL.object_id = FKC.parent_object_id AND FK_COL.column_id = FKC.parent_column_id
    JOIN sys.columns REFERENCED_COL ON REFERENCED_COL.object_id = FKC.referenced_object_id AND REFERENCED_COL.column_id = FKC.referenced_column_id
    WHERE REFERENCED_TABLE.name = 'Table_Name'
)
SELECT
    ForeignKeyName,
    'ALTER TABLE [' + ForeignKeySchema + '].[' + ForeignKeyTable + '] ' +
    'ADD CONSTRAINT [' + ForeignKeyName + '] FOREIGN KEY ([' + ForeignKeyColumn + ']) ' +
    'REFERENCES [' + ReferencedSchema + '].[' + ReferencedTable + '] ([' + ReferencedColumn + ']);'
    AS ForeignKeyScript,

    'ALTER TABLE [' + ForeignKeySchema + '].[' + ForeignKeyTable + '] ' +
    'DROP CONSTRAINT [' + ForeignKeyName + '];' AS ForeignKeyDropScript
FROM ForeignKeyInfo
ORDER BY ForeignKeyName, ColumnPosition;

-- instead of
SUM(SomeField)

--use
SUM(CAST(SomeField as bigint))

SELECT 
    select_list
INTO 
    destination
FROM 
    source
[WHERE condition]

SELECT
    FKTable.[name] AS ForeignKeyTable,
    FKCol.[name] AS ForeignKeyColumn
FROM
    sys.tables AS PKTable
JOIN
    sys.columns AS PKCol ON PKTable.[object_id] = PKCol.[object_id]
JOIN
    sys.foreign_key_columns AS FK ON PKTable.[object_id] = FK.[referenced_object_id]
                                        AND PKCol.[column_id] = FK.[referenced_column_id]
JOIN
    sys.tables AS FKTable ON FKTable.[object_id] = FK.[parent_object_id]
JOIN
    sys.columns AS FKCol ON FKTable.[object_id] = FKCol.[object_id]
                            AND FK.[parent_column_id] = FKCol.[column_id]
WHERE
    PKTable.[name] = '<Your_Table>'
    AND PKCol.[name] = 'Id'
ORDER BY
    ForeignKeyTable,
    ForeignKeyColumn;